#188 Declarative Authorization - RailsCasts

authorization do role :admin do has_permission_on [:articles, :comments], :to => [:index, :show, :new, :create, :edit, :update, :destroy] end role :guest do has_permission_on :articles, :to => [:index, :show] has_permission_on :comments, :to => [:new, :create] has_permission_on :comments, :to => [:edit, :update] do if_attribute :user => is { user } end end role :moderator do includes :guest has_pe