Include and Extend Ruby mixin

mixin.rb

module Foo
  def say 
    'foo'
  end
end

module Bar
  def say 
    'bar'
  end
end

class Baz
  include Foo
end

baz = Baz.new
puts baz.say

bazzer = Baz.new
bazzer.extend(Bar)
puts bazzer.say