association

# File activerecord/lib/active_record/associations.rb, line 313
    def association(name) # :nodoc:
      association = association_instance_get(name)

      if association.nil?
        unless reflection = self.class._reflect_on_association(name)
          raise AssociationNotFoundError.new(self, name)
        end
        association = reflection.association_class.new(self, reflection)
        association_instance_set(name, association)
      end

      association
    end