I am practicing how to build Discourse plugin it's not useful code for you.
https://meta.discourse.org/t/beginners-guide-to-creating-discourse-plugins-part-4-git-setup/31272
Put entire folder under discourse/plugin/
and you are good to go. rails s
to start server
At the time build this, Newest Discourse version: v2.0.0.beta7
(https://github.com/discourse/discourse/releases)