--- included(class_or_module)  ruby 1.7 feature

    self  include 줿ȤоݤΥ饹ޤϥ⥸塼
    ˥󥿥ץ꥿ƤӽФޤ

        module Foo
          def self.included(mod)
            p "#{mod} include #{self}"
          end
        end
        class Bar
          include Foo
        end
        # => "Bar include Foo"

