Allow sites to be removed

[acrogenesis]

Fixes #4
Using the url kaffeine.herokuapp.com/decaf/:name you can remove your app from kaffeine. I also update rails

[romainbutteaud]

Awesome! Thank you @acrogenesis! :)
Now we would need some information on the front page to explain the user how to remove the app.

[acrogenesis]

@romainbutteaud ready, here is a preview of how it works:
https://www.youtube.com/watch?v=Y1U7npaSqE0

[acrogenesis]

bump

[romainbutteaud]

Thanks @acrogenesis for your contribution. Since "decaf" will rarely be used I would rather put a link in the footer:
After "Thanks for sharing!", put a link "Decaf" that shows a nice modal with the input and the button to remove the app. What do you think?

[acrogenesis]

Seems great to me, I'll update the PR in a moment

[acrogenesis]

@romainbutteaud done

[malolans]

Is there a time line on when this pull request would be merged? I would like to remove my app from kaffeine.

Thanks!

[romainbutteaud]

@acrogenesis @malolans merging 👍

[malolans]

Thanks!