Lookup Active Record Query Interface http://guides.rubyonrails.org/active_record_querying.html
ActiveRecord::QueryMethods http://api.rubyonrails.org
Class methods http://api.rubyonrails.org/classes/ActiveRecord/Scoping/Named/ClassMethods.html
Lookup Active Record Query Interface http://guides.rubyonrails.org/active_record_querying.html
ActiveRecord::QueryMethods http://api.rubyonrails.org
Class methods http://api.rubyonrails.org/classes/ActiveRecord/Scoping/Named/ClassMethods.html