ruby on rails - How do i add a new action to an already created controller? -

I am using rail and I have to know how to add a new action to my controller, in the rail I'm starting I'm not really aware that I just "DEF action" controller. I am typing in RB or else he is the same?

Thanks

No, this is it ... just a controller class To add a method to automatically add a new action to that controller (with at least the default setup)

This book has a small section about it. Also, reading through the ruby ​​on the train might be useful.