Add rolify gem
Generate Role model
Modify models for rolify
Add authority gem
Generate authority
Modify models for authority
Update application controller
Update auth view and User model
Add home authorizer
Add test users controller
Add users resourses to routes
Add authorizer for users
Update user authorizer
Protect action
Set model authorizer
Add admin controller
Add admin resource to routes
Add 'Become user' valid link
Set sign_out_all_scopes to false
Refactor application controller