class associations apart from models

I want to use several custom classes in the controller. Some of them are supposed to have certain associations. I know how to work with associations in the model and I thought that I could do something similar here.

What I tried is something like this:

module Types

  class System < ActiveRecord::Base     has_many :resources     attr_accessor :name     def initialize(name)       @name = name     end   end

  class Resource < ActiveRecord::Base     belongs_to :system     attr_accessor :name     def initialize(name,system)       @name = name       # add to system (?)     end   end


So how can I specity the System for a Resource or return it?

Thanks, Max