how to load a controller in another controller in ruby on rails

Like php we can import all the functionality of a simple php file name as myfile.php in another file index.php using require "", require_once "", include "" and include_once "". Like this in ruby on rails I want to import a controller file name as products_controller.rb in a another controller file name as home_controller.rb . both files present in the app/controller directory. In shot i want to import a controller file in another controller file to use all the functions of included controller file