Warden Delegated

This is a minimal Warden configuration used to delegate authentication to another app that is running Devise. Extracted from a production environment.

Steps:

1. Add to Gemfile gem 'warden_delegated'
2. Configure your applications to share sessions
3. Set the LOGIN_URL environment variable
4. Add include Warden::Delegated::Model in your user model
5. Add initializer like below

Put the following in an initializer(assumes :user scope and User model):

Rails.application.config.middleware.use Warden::Manager do |manager|
  manager.failure_app = Warden::Delegated::FailureApp.new
  manager.default_scope = :user
  manager.default_strategies :delegated
  manager.serialize_from_session(:user) do |key|
    User.serialize_from_session(key)
  end
end

1. Write some tests