Devise token authenticatable initial config
Used ngTokenAuth and devise_toke_auth to implement token based authentication. Various refactorings were needed
Implemented authentication check in PostsController. / route is now protected against unauthenticated user. There's no notification yet for unauthenticated requests
Added Authentication interceptor to intercept 401 statuses. Upon a 401 an 'event:unauthenticated' is broadcasted from rootScope. Main application listens for that event and redirects to /login. UsersService, instead, logs out. Modified userPanel directive to listen for user:unset and act accordingly.