Install and configure Doorkeeper

The gem has been installed, and the generator has been run. Doorkeeper has been configured to work with devise, and to allow all apps automatically.
Generate doorkeeper views

The views have been added to the app to allow customization in the future.
Generate UsersController

This controller handles interaction with the User model, and provides a callback for OAuth to request additional information about a user.
Implement callback for OAuth

An action has been added that OAuth uses to request additional information about a user that has just been authenticated.
Fix bug in OAuth callback action

The respond_to syntax was messed up, resulting in a runtime error.
Add template for users#me

This action returns the current resource owner as a JSON object. A template has been added that defines how the JSON response looks.
Install Jbuilder

JBuilder makes it easy to create JSON views.
Merge branch 'feature/integrate-doorkeeper' into develop