class_module_include.rb

class Task
  class Hoge
    def self.hoge
      puts "hoge!!!!"
    end
  end

  module Foo
    def foo
      Hoge.hoge
    end
  end
end

class Task
  class Fuga
    include Foo
    def jjj
      foo
    end
  end
end

Task::Fuga.new.jjj #=> hoge!!!!