Description:

Adds boilerplate controllers, models, and views for authenticating a model.

Example:

rails generate authentication Member

This will create:
    app/models/concerns/authenticateable.rb
    app/controllers/concerns/authentication.rb
    app/controllers/members/sessions_controller.rb
    app/models/member_session.rb
    app/views/members/sessions/new.html.slim
    spec/system/members/authentication_spec.rb
    spec/models/member_session_spec.rb