Error: MartialArts is not a module


#1
I keep getting the Error: MartialArts is not a module
Anybody can explain me why?

Here is my code:

module MartialArts
    def swordsman
        puts "I'm a swordsman."
    end
end

class Ninja
  include MartialArts
  def initialize(clan)
    @clan = clan
  end
end

class Samurai
  include MartialArts
  def initialize(shogun)
    @shogun = shogun
  end
end

#2

I don't know what's wrong with your code, I've tried it here and it works good.