DEMO => githubcleaner.com/
1 - Create Github API key here:
github.com/settings/applications
2 - After you’ve created a key for your app on Github, specify this callback:
localhost:3000/auth/github/callback
3 - Enter your Github API key and secret here:
config/initializers/omniauth.rb
4 - Run your migrations, and start your server
5 - Go to localhost, and click on “Authenticate via Github”
6 - Success! You should see a list of your repos at /users/show