elixirschool/school_house

The new era of Elixir School now powered by @phoenixframework

Elixir School

Elixir School is the premier destination for people seeking to learn and master the Elixir programming language.

You can access lessons at ElixirSchool.com.

Feedback and participation are strongly encouraged! Please see Contributing for more details on how to get involved.

Running Locally

This repository only contains the lessons and blog posts hosted on Elixir School. To run the Elixir School website locally, find the code and setup instructions in the school_house repository.

Translating a Lesson

1. Each of the languages has a folder in lessons/ directory of this repo. To start translating you need to copy a file from the English language to the corresponding folder in your language and start translating it.

2. Check the translation report for pages that haven't been translated yet, or for pages which need to have their translations updated in the corresponding language you want to work with.

3. Translated lessons must include page metadata.

   • title should be a translation of the original lesson's title.
   • version should be set to the original English version.

   For example lessons/ja/basics/basics.md:

---
title: 基本
version: 1.0.0
---

4. Submit a PR with the new translated lesson 🎉

Posting an Article

Elixir School is powered by Phoenix and NimblePublisher, a publishing engine that supports Markdown formatting. If you're familiar with Phoenix & NimblePublisher then you're ready to go, if you aren't don't fret we're here to help!

1. We need to create the file for our article. Blog posts live in the posts/ directory. Our filename will need to confirm to the YYYY-MM-DD-name-separated-with-hyphens.md pattern.

2. After opening the new file in our favorite editor we need to add some metadata to the top of it:

%{
  author: "Author Name",
  author_link: "https://github.com/author_github_account",
  tags: ["phoenix"],
  date: ~D[YYYY-MM-DD],
  title: "Full Article Title",
  excerpt: """
  Article short preview text
  """
}
---

3. Once we've completed writing our post submit a pull request to have it reviewed before it is published.

school_house's Issues

Table of contents fails on international characters

Detected on https://rocketvalidator.com/s/4ec0b390-f775-4db1-87a4-ced8f5ece619/p/4686420/i

It looks like the tables of contents for lessons does not generate the headings when those contain non-English characters.

While in the legacy site it works fine:

https://elixirschool.com/es/lessons/specifics/mnesia/#inicialización-de-datos-y-migración

the beta site doesn't work OK:

https://beta.elixirschool.com/es/storage/mnesia

Headings containing non-English characters like "inicialización" are not being generated.

Add a 404 page for missing lessons with a translation CTA

Dark mode white flash

How can we avoid that white flash when browsing in dark mode?

I'm not sure how the dark mode is activated, but it looks like each request renders the pages in white mode and then it's switched to dark, which is quite confusing.

Road to Launch

I'm going to use this issue to outline what remains to get this iteration of Elixir School live 🚀

Must Have

1. Update Lessons menu to be more responsive. cc @burden
2. Move gettext into external repo to keep translation materials together. Note: The downside here is keeping them updated. I will tackle this.
3. Automated deploys for changes to both repositories #20
4. Announcement blog post

Nice to Have

1. Add code examples to homepage and Why Elixir? pages #32
2. Blog RSS feed. We have this currently so it would be a loss of functionality for a short time. I could see this being move to Must Have. #54
3. Sitemap.xml #62
4. Expand on the Why Elixir and homepage copy
5. Document project

Update `_header.html.eex` to finish integrating the `lesson_link/3` helper

This helper handles disabling links for lessons missing and translations. Right now it's only partially implemented as I just needed enough to test. We probably want to do #3 first and then this since this relies on that.

GR is not a valid ISO language code - use EL instead

Caught here:

https://rocketvalidator.com/s/0bdee490-cff7-495a-95a3-40211cd2b5cd/i/112946387

Correct code for Greek seems to be el.

Add a link to the blog in Recent Blog post section on the homepage

We should add a CTA here to explore the blog further:

HTML issues with meta tags

The most common HTML issues we have are related with <meta> tags generated by Phoenix:

https://rocketvalidator.com/s/0bdee490-cff7-495a-95a3-40211cd2b5cd/i?search=meta

There are all sort of issues but in the end it's just one line in the layout:

https://github.com/elixirschool/school_house/blob/master/lib/school_house_web/templates/layout/root.html.leex#L6

<%= csrf_meta_tag() %>

This function comes from PhoenixHTML, and is documented here:

https://hexdocs.pm/phoenix_html/Phoenix.HTML.Tag.html#csrf_meta_tag/0

Now, trouble with this meta tag is that the W3C HTML Validator says it's malformed. You can see by yourself on https://validator.w3.org/nu/#textarea and checking this example HTML:

<!DOCTYPE html>
<html lang="">
<head>
<title>Test</title>
<meta charset="UTF-8" content="ASonEyRBAAJaA2srAAZrZlkhYmYeGHUFHdsgU5uN9iYdN_3_tRV_njE_" csrf-param="_csrf_token" method-param="_method" name="csrf-token">
</head>
<body>
<p></p>
</body>
</html>

This raises 4 errors:

• Attribute csrf-param not allowed on element meta at this point.
• Attribute method-param not allowed on element meta at this point.
• Attribute name not allowed on element meta at this point.
• Attribute content not allowed on element meta at this point.

I see those options:

1.- Muting all those issues

We can just accept that this is generated by Phoenix so we won't fix those issues, and just mute them.

2.- Try to generate valid meta tags

What I do on the RV site is change it to:

<meta charset="UTF-8">
<meta content="<%= get_csrf_token() %>" name="csrf-token">

which fixes the issues, it moves the charset declaration to its own tag as expected, and simplifies the one for the CSRF token. But we would be missing the csrf-param="_csrf_token" method-param="_method" which I'm not sure how they're generated.

What do you think?

Implement dark mode

This is a popular feature on the existing site, we should be sure to port it. I believe TailwindCSS has something built in to make this easier 🤞

Improve responsiveness

The focus has been just the desktop experience so far. We need to revisit all of the markup to improve the tablet and phone experience.

Add a Conferences directory

I'd like to add a page that lists conferences for Elixir and the BEAM ecosystem. A couple thoughts we could think about and consider:

1. Allow sorting by country
2. Online vs in-person sorting
3. List each time and place the conference has occurred. This helps people tell which ones are established and which are newer.
4. Consider listing previous talks and link to the videos/content?
5. ???

Enable Filtering for Blog Posts

Right now in the footer of the website there are three links that should link to a list of blog posts filtered by their associated tag. We need to implement the filtering logic and update the following links:

• Blog > Announcements
• Blog > Today I Learned
• Blog > Reviews

Split from #73

HTML / A11Y issues

OK so now that the broken links have been fixed, I've run a new HTML & Accessibility validation report, I'm leaving this as a reference:

https://rocketvalidator.com/s/150a8d31-1783-4adb-bf26-77641ed567b0

I'll be working on fixing those issues in separate PRs - note however that for some of the issues we may just want to mute them if we're OK with them, for example custom attributes in Phoenix like phx-*.

Implement the translation report in Phoenix

This shouldn't be too difficult now to do with Tailwind and Phoenix 🎉

HTML / Accessibility validation

Hello!

As we talked in #35 we're using Rocket Validator to check for HTML and Accessibility issues in the new site for Elixir School.

I've set up a weekly schedule to run site-wide reports, and the new domain stats feature (now in beta) gives the latest reports run for that domain, and some nice stats showing the evolution in the number of issues and check coverage.

Here's the direct link to the latest stats and reports for that domain:

https://rocketvalidator.com/domains/elixirschool.com?auth=171c6160-f0a2-49d9-b83f-065c15c8a072

@doomspork feel free to replace this with your own shared link, so that we get the data from reports in your account, which I believe should be our main reference.

RuntimeError

Message

  ** (RuntimeError) expected action/2 to return a Plug.Conn, all plugs must receive a connection (conn) and return a connection, got: nil

Backtrace (last 10 lines)

lib/school_house_web/controllers/post_controller.ex:1 SchoolHouseWeb.PostController.phoenix_controller_pipeline/2
lib/phoenix/router.ex:352 Phoenix.Router.__call__/2
lib/school_house_web/endpoint.ex:1 SchoolHouseWeb.Endpoint.plug_builder_call/2
lib/school_house_web/endpoint.ex:3 anonymous fn/3 in SchoolHouseWeb.Endpoint."call (overridable 3)"/2
lib/appsignal/instrumentation.ex:10 Appsignal.Instrumentation.instrument/1
lib/school_house_web/endpoint.ex:1 SchoolHouseWeb.Endpoint."call (overridable 4)"/2
lib/plug/error_handler.ex:65 SchoolHouseWeb.Endpoint.call/2
lib/phoenix/endpoint/cowboy2_handler.ex:65 Phoenix.Endpoint.Cowboy2Handler.init/4

View on AppSignal: https://appsignal.com/elixirschool/sites/6073b19e14ad66590ce95ae9/exceptions/incidents/8?timestamp=2021-04-15T10:05:21Z

Create a Mix Task to generate a sitemap.xml

This would need to include all of the blog posts, every lesson + locale variant, and other supplement pages.

Duplicate IDs in table of contents

There are some duplicate IDs generated by the table of contents for the lessons:

https://rocketvalidator.com/s/0bdee490-cff7-495a-95a3-40211cd2b5cd/i?search=duplicate+ID

For example, in https://beta.elixirschool.com/en/ecto/associations there are 2 sections titled "Many to Many":

• Types of Associations > Many To Many
• Saving Associated Data > Many To Many

Clicking on those will always get you to the first one, as the second is a duplicate.

In order to fix this we need to give a unique ID to each section. I'm not sure how to do that, maybe including numbers, like:

1. Set Up
2. Types of Associations
   2.1 Belongs To/Has Many
   2.2.1 The Has Many Migration
   2.2.1 The Has Many Schema

...

Broken links in sitemap.xml

The latest report by RV has found many broken links, where the locale part is at the end of the URL

https://rocketvalidator.com/s/624562a6-bdbe-4411-9c28-3652a4887982/p?page=1&search=&sort=url-asc

We need to find where these URLs are being generated and fix that.

Error on populate_surrounding_lessons

Some lesson URLs are raising an error:

https://beta.elixirschool.com/ru/ecto/querying_basics

[error] #PID<0.18017.0> running SchoolHouseWeb.Endpoint (connection #PID<0.18016.0>, stream id 1) terminated
Server: elixirschool-jaime.ngrok.io:80 (http)
Request: GET /ru/ecto/querying_basics
** (exit) an exception was raised:
    ** (ArithmeticError) bad argument in arithmetic expression
        (school_house 0.1.0) lib/school_house/lessons.ex:113: SchoolHouse.Lessons.populate_surrounding_lessons/1
        (school_house 0.1.0) lib/school_house/lessons.ex:48: SchoolHouse.Lessons.get/3
        (school_house 0.1.0) lib/school_house_web/controllers/lesson_controller.ex:16: SchoolHouseWeb.LessonController.lesson/2
        (school_house 0.1.0) lib/school_house_web/controllers/lesson_controller.ex:1: SchoolHouseWeb.LessonController.action/2
        (school_house 0.1.0) lib/school_house_web/controllers/lesson_controller.ex:1: SchoolHouseWeb.LessonController.phoenix_controller_pipeline/2
        (phoenix 1.5.9) lib/phoenix/router.ex:352: Phoenix.Router.__call__/2
        (school_house 0.1.0) lib/school_house_web/endpoint.ex:1: SchoolHouseWeb.Endpoint.plug_builder_call/2
        (school_house 0.1.0) lib/school_house_web/endpoint.ex:3: anonymous fn/3 in SchoolHouseWeb.Endpoint."call (overridable 3)"/2
        (appsignal 2.1.7) lib/appsignal/instrumentation.ex:10: Appsignal.Instrumentation.instrument/1
        (school_house 0.1.0) lib/plug/debugger.ex:136: SchoolHouseWeb.Endpoint."call (overridable 4)"/2
        (school_house 0.1.0) lib/school_house_web/endpoint.ex:1: SchoolHouseWeb.Endpoint."call (overridable 5)"/2
        (school_house 0.1.0) lib/plug/error_handler.ex:65: SchoolHouseWeb.Endpoint.call/2
        (phoenix 1.5.9) lib/phoenix/endpoint/cowboy2_handler.ex:65: Phoenix.Endpoint.Cowboy2Handler.init/4
        (cowboy 2.9.0) /Users/jaime/code/elixirschool/school_house/deps/cowboy/src/cowboy_handler.erl:37: :cowboy_handler.execute/2
        (cowboy 2.9.0) /Users/jaime/code/elixirschool/school_house/deps/cowboy/src/cowboy_stream_h.erl:306: :cowboy_stream_h.execute/3
        (cowboy 2.9.0) /Users/jaime/code/elixirschool/school_house/deps/cowboy/src/cowboy_stream_h.erl:295: :cowboy_stream_h.request_process/3
        (stdlib 3.14.2) proc_lib.erl:226: :proc_lib.init_p_do_apply/3

Locale menu generates broken links

When working at validation I was surprised to see that Rocket Validator had found 4,273 web pages in the site so I decided to have a look at the list of web pages found.

The web page URLS definitely look weird:

"announcemtat", "announcemvit", "phonoix", "phoplix"... That seems to be caused by the way we're generating the URLs for the pages in other languages, changing "en" by the language code:

• phoenix -> phoplix ("en" -> "pl")

When a page can't be found, the site is still responding with 200 OK instead of 404 Not Found as it should, which explains why Rocket Validator picked the web page and still validated the content:

➔ curl -i https://beta.elixirschool.com/blog/elixirconf-announcemskt
HTTP/2 200 
date: Fri, 23 Jul 2021 08:43:18 GMT

So in order to fix this we need to:

1.- Fix locale menu URLs
2.- Return 404 on pages not found

I'll work on that.

Phoenix.Template.UndefinedError happened in SchoolHouseWeb.LessonController#lesson

Message

  ** (Phoenix.Template.UndefinedError) Could not render "404.html" for SchoolHouseWeb.LessonView, please define a matching clause for render/2 or define a template at "lib/school_house_web/templates/lesson/*". The following templates were compiled:

* _section_header.html
* lesson.html

Assigns:

%{conn: %Plug.Conn{adapter: {Plug.Cowboy.Conn, :...}, assigns: %{layout: {SchoolHouseWeb.LayoutView, "app.html"}}, before_send: [#Function<0.36096693/1 in Plug.CSRFProtection.call/2>, #Function<2.107009429/1 in Phoenix.Controller.fetch_flash/2>, #Function<0.29283909/1 in Plug.Session.before_send/2>, #Function<0.24098476/1 in Plug.Telemetry.call/2>], body_params: %{}, cookies: %{}, halted: false, host: "beta.elixirschool.com", method: "GET", owner: #PID<0.3709.0>, params: %{"locale" => "ar", "name" => "documartation", "section" => "basics"}, path_info: ["ar", "basics", "documartation"], path_params: %{"locale" => "ar", "name" => "documartation", "section" => "basics"}, port: 80, private: %{SchoolHouseWeb.Router => {[], %{}}, :phoenix_action => :lesson, :phoenix_controller => SchoolHouseWeb.LessonController, :phoenix_endpoint => SchoolHouseWeb.Endpoint, :phoenix_flash => %{}, :phoenix_format => "html", :phoenix_layout => {SchoolHouseWeb.LayoutView, :app}, :phoenix_request_logger => {"request_logger", "request_logger"}, :phoenix_root_layout => {SchoolHouseWeb.LayoutView, :root}, :phoenix_router => SchoolHouseWeb.Router, :phoenix_template => "404.html", :phoenix_view => SchoolHouseWeb.LessonView, :plug_session => %{}, :plug_session_fetch => :done}, query_params: %{}, query_string: "", remote_ip: {0, 0, 0, 0, 0, 65535, 2590, 10351}, req_cookies: %{}, req_headers: [{"accept-encoding", "gzip"}, {"cdn-loop", "cloudflare"}, {"cf-connecting-ip", "100.24.30.204"}, {"cf-ipcountry", "US"}, {"cf-ray", "63fda754adf6551e-EWR"}, {"cf-request-id", "097266e8ea0000551e18976000000001"}, {"cf-visitor", "{\"scheme\":\"https\"}"}, {"connect-time", "1"}, {"connection", "close"}, {"host", "beta.elixirschool.com"}, {"total-route-time", "0"}, {"user-agent", "RocketValidator/Spider (+https://rocketvalidator.com)"}, {"via", "1.1 vegur"}, {"x-forwarded-for", "100.24.30.204, 162.158.62.42"}, {"x-forwarded-port", "80"}, {"x-forwarded-proto", "http"}, {"x-request-id", "8459bf4c-b512-4983-bf71-c056aa104644"}, {"x-request-start", "1618410852637"}], request_path: "/ar/basics/documartation", resp_body: nil, resp_cookies: %{}, resp_headers: [{"cache-control", "max-age=0, private, must-revalidate"}, {"x-request-id", "8459bf4c-b512-4983-bf71-c056aa104644"}, {"x-frame-options", "SAMEORIGIN"}, {"x-xss-protection", "1; mode=block"}, {"x-content-type-options", "nosniff"}, {"x-download-options", "noopen"}, {"x-permitted-cross-domain-policies", "none"}, {"cross-origin-window-policy", "deny"}], scheme: :http, script_name: [], secret_key_base: :..., state: :unset, status: nil}, view_module: SchoolHouseWeb.LessonView, view_template: "404.html"}

Assigned keys: [:conn, :view_module, :view_template]

Backtrace (last 10 lines)

lib/phoenix/template.ex:337 Phoenix.Template.raise_template_not_found/3
lib/appsignal/instrumentation.ex:10 Appsignal.Instrumentation.instrument/1
lib/phoenix/view.ex:310 Phoenix.View.render_within/3
lib/phoenix/controller.ex:788 Phoenix.Controller.render_with_layouts/4
lib/phoenix/controller.ex:776 Phoenix.Controller.render_and_send/4
lib/school_house_web/controllers/lesson_controller.ex:1 SchoolHouseWeb.LessonController.action/2
lib/school_house_web/controllers/lesson_controller.ex:1 SchoolHouseWeb.LessonController.phoenix_controller_pipeline/2
lib/phoenix/router.ex:352 Phoenix.Router.__call__/2

View on AppSignal: https://appsignal.com/elixirschool/sites/6073b19e14ad66590ce95ae9/exceptions/incidents/7?timestamp=2021-04-14T14:34:12Z

Populate Remaining Empty Links

There are several links on the home page that have no corresponding page on the website. @doomspork should we create new pages for each of them?

Here are the ones I've noticed - I may be missing a few:

Header:

• Get Involved
• Support

Footer:

• Blog > Announcements
• Blog > Today I Learned
• Blog > Reviews
• Project > Contributors
• Project > Get Involved
• Project > Support

Error during make setup

I was setting up the repo and run into this when running make setup:

== Compilation error in file lib/school_house/lessons.ex ==
** (ArgumentError) argument error
    :erlang.binary_to_integer("Elixir School")
    (elixir 1.12.0) lib/enum.ex:1553: Enum."-map/2-lists^map/1-0-"/2
    lib/school_house/content/lesson.ex:77: SchoolHouse.Content.Lesson.parse_version/1
    lib/school_house/content/lesson.ex:36: SchoolHouse.Content.Lesson.build/3
    (nimble_publisher 0.1.1) lib/nimble_publisher.ex:44: anonymous fn/3 in NimblePublisher.__extract__/2
    (elixir 1.12.0) lib/enum.ex:2356: Enum."-reduce/3-lists^foldl/2-0-"/3
    (nimble_publisher 0.1.1) lib/nimble_publisher.ex:41: NimblePublisher.__extract__/2
    lib/school_house/lessons.ex:31: (module)
    lib/school_house/lessons.ex:31: anonymous fn/2 in :elixir_compiler_43.__MODULE__/1
    (elixir 1.12.0) lib/enum.ex:2356: Enum."-reduce/3-lists^foldl/2-0-"/3
    lib/school_house/lessons.ex:11: (module)
make: *** [setup] Error 1

Table of contents does not properly handle sections with `` in the name

There's a few pages where the section header is an inline code fragment like if, these are not being handled by the table of contents code correctly because they become nested tags.

I think there's 2 options here:

1. We update all of those lessons to no longer make use of the `` in section headers. This also unifies the styling of all the table of contents and headers.
2. Work through the parsing logic to support them. The most challenge example if the section "if and unless"

Add new pages to sitemap.xml

The new https://beta.elixirschool.com/en/get_involved URL and all their translations should be added to https://beta.elixirschool.com/sitemap.xml

Update `config/lessons.exs` with the new lesson structure

Right now it reflects the existing lesson structure, not the one we want to move to.

ArithmeticError happened in SchoolHouseWeb.LessonController#lesson

Message

  ** (ArithmeticError) bad argument in arithmetic expression

Backtrace (last 10 lines)

lib/school_house/lessons.ex:42 SchoolHouse.Lessons.populate_surrounding_lessons/1
lib/school_house_web/controllers/lesson_controller.ex:7 SchoolHouseWeb.LessonController.lesson/2
lib/school_house_web/controllers/lesson_controller.ex:1 SchoolHouseWeb.LessonController.action/2
lib/school_house_web/controllers/lesson_controller.ex:1 SchoolHouseWeb.LessonController.phoenix_controller_pipeline/2
lib/phoenix/router.ex:352 Phoenix.Router.__call__/2
lib/school_house_web/endpoint.ex:1 SchoolHouseWeb.Endpoint.plug_builder_call/2
lib/school_house_web/endpoint.ex:3 anonymous fn/3 in SchoolHouseWeb.Endpoint."call (overridable 3)"/2
lib/appsignal/instrumentation.ex:10 Appsignal.Instrumentation.instrument/1

View on AppSignal: https://appsignal.com/elixirschool/sites/6073b19e14ad66590ce95ae9/exceptions/incidents/5?timestamp=2021-04-15T14:56:44Z

Beta site is down

Hey https://beta.elixirschool.com/ is down...

Code examples for homepage and "why elixir?"

It would be good to identify some examples we can use both on the homepage and the "why elixir?" page to help highlight the features and beauty of the language.

Suggestions for improving the blog

What are some possible improvements to the blog that would help with content discoverability?

Some ideas off the top of my head:

1. Tag cloud
2. Posts by Author
3. Pagination of blog
4. In addition to Recent posts, display a small number of random posts

Implement RSS feed support for the blog

We have this one the existing site. It would be great to get this moved over.

See: https://github.com/elixirschool/elixirschool/blob/master/feed.xml

Docker build is broken

While I had tested #60 I must have missed something as docker no longer builds and as such deploys are broken. I'll try to look into this tonight 👍

Satisfy Credo CI check

There's currently a few things Credo is complaining about, those need to get cleaned up in order to get CI green.

We can also evaluate modifications to the Credo config if we're unhappy with the defaults.

Homepage stats on Elixir adoption and community

To help drive home the awesomeness of Elixir, the community, and the ecosystem as a whole stats would be great. Some ideas:

• Number of conferences
• Number of podcasts
• Number of translations on Elixir School
• Number of companies (see: elixir-companies.com)
• Number of countries with an Elixir presence (meetups/conference/etc)
• Number of Hex packages

Trigger Heroku Deploy Action on merge of elixirschool/elixirschool repo.

This likely needs to wait till the rest of this is complete and move the entire "legacy" repo to the new content. When changes to a lesson or blog post are merged, we need to trigger a deploy of this repository.

Broken links to port 80

I've run a Rocket Validator report on the beta site, and the crawler has found some broken links, on pages that use the 80 port:

https://rocketvalidator.com/s/5a71bc62-29c6-4e85-9ce5-2af0513f1976

Not sure yet if these are direct links or redirections, any idea?

Accessibility Suggestions

Thanks to Mikolaj Holysz for taking the time to check out the beta site and compile some accessibility-related notes 🎉 !

Here are the notes 🗒️ .

I have already tackled my lanuages typo 😅.

Elixir version?

I think we should set a required Elixir version, currently in mix.exs it says 1.7.0 but that's quite old, is there any reason not to use 1.12?

Maybe we can add a .tool-versions file like it's done in asdf, or maybe it's enough with specifying it in the README?

Increasing contrast

Our main accessibility issue is low contrast in some parts of the text, specially code:

https://rocketvalidator.com/s/2f3a096c-1324-48e9-ace7-e8f0d6385eee/v/15063853

I'm working on increasing the contrast of some colors, but it would really help if we increased the font size a bit in general. What do you think? Is there a CSS class to set the base font size?

Add a Podcast directory

Following up on #51 it would be awesome to do the same for Podcasts.

Broken images in blog posts

There are some blog posts where the images are not being properly rendered:

https://rocketvalidator.com/s/0bdee490-cff7-495a-95a3-40211cd2b5cd/i?search=Bad+value+“%7B%25+&page=1&non_doc=false

It complains about "Bad value “{% asset " and the images are broken. For example in https://beta.elixirschool.com/blog/live-view-with-channels

This doesn't happen in the main site, https://elixirschool.com/blog/live-view-with-channels so I guess these tags were only valid in Jekyll?

Integrate AppSignal

We have an AppSignal account we should set this project up with.

Locale menu should validate current locale

https://beta.elixirschool.com/klingon makes it think like we're supporting that language, but we're not :D

Add scroll to top links on each section

@burden might be working on this.

Create "Get Involved" Page

We should create a page that describes how someone can contribute to elixir school. These include:

• Translations. This could include steps to how to translate or link out to another new page depending on how much content we have for that.
• New content. This could direct people to the Issues on the content repo maybe with a new-lesson label filter?
• Blog posts.
• ??

Split from #73

Add Previous and Next lesson links.

The lesson is already set up to contain the next and previous lessons, we just need to add the UI. Additionally I parsed all the lessons and pulled the first paragraph (above the TOC) out and into the excerpt attribute. This allows us to display this along with these links.

I'll work on tackling this next.

Trigger HTML / A11Y validation on deploys

Related to #20 I think we could also add a webhook to notify of deploys on Rocket Validator. This way, an automatic report looking for HTML / Accessibility issues can be run. Here's more info, but basically we just need to POST to an URL that contains the trigger:

https://docs.rocketvalidator.com/deploy-hooks/

I can set this up if that sounds like a good idea. All I need to know are the main URLs to validate (production, staging...)

Add locale selector to UI

We need to provide a way for user's to select a different locale from the header.

Implement a Redirect Plug to handle the `redirect_from` logic in Jekyll

We need to handle all the redirects we have in the existing project. I think we could pull this out of all the lessons and maintain a single config/redirects.exs file that would be leveraged by a Plug.