Redirect to request.fullpath instead of request.path

Imagine your application is an OAuth provider and application *ABC* will use you as the authentication service.  

From ABC, the user will get redirected to `oauth/authorize` with the needed params (`client_id`, `scope`, and others). If the user is not logged in, the provider will show the login form and after a successful login, the user should be redirected to `/ouath/authorize?client_id=123&scope=public` and not to `/oauth/authorize`, since this route is invalid.

@bcardarella what do you think about this?