ruby extend
module ReusableModule
  def module_method
    puts "Module Method: Hi there!"
  end
end
class ClassThatIncludes
  include ReusableModule
end
class ClassThatExtends
  extend ReusableModule
end
puts "Include"
ClassThatIncludes.new.module_method       # "Module Method: Hi there!"
puts "Extend"
ClassThatExtends.module_method            # "Module Method: Hi there!"
