module AssociateWithList
  def associate_with_list(column_name, list_name)
    define_method "#{column_name}_list" do
      items = AssociatedListItem.find(:all, :conditions => "list_name = '#{list_name}'").collect { |i| i.value.to_s }
    end

    define_method "add_#{column_name}_to_list" do
      value = self.send(column_name.to_sym)
      item = AssociatedListItem.find_or_create_by_list_name_and_value(list_name, value)
    end

    eval "after_save add_#{column_name}_to_list"
  end
end