update examples to koa@2

[koajs]

update examples to koa@2

[haoxins]

I'll update all examples to koa@2 next weekend :)

Also, PRs welcome! 😄

[bananaappletw]

@DoumanAsh Hi, I just created koa2-example.
I will try to migrate koa examples to koa2 in my available time.

[bananaappletw]

@coderhaoxin Hi, I already migrate some examples.
You could setup the initial process of migrating this repo to koa@2 (babel, eslint ......).
Then I could send the pull request for the examples I migrated.
Thanks for the enhancement of this repo.

[bananaappletw]

@coderhaoxin Or, you want to remain the this repo for koa1.
I could transfer my current repo (already migrate some examples for koa2) to koa organization.
And continue my migration work on koa organization.
What do you think about it?

[haoxins]

I'd rather just create a branch such as koa-v1 for koa@v1 :)

@bananaappletw 👍
Feel free to submit PRs to master for your migration. ((>_<))

[bananaappletw]

@coderhaoxin Could you create koa-v1 branch in this repo?
At least, we should backup koa@v1 examples before migrate master branch to koa2.
Just copy current master to koa-v1.
I don't have privilege to do that.
Then, I send the pull request to master.
Thanks.

[haoxins]

Could you create koa-v1 branch in this repo?

DONE :)

[haoxins]

50bcadf