Challenge 1: A Loggable Module — Solution

module Loggable
  def log(message)
    puts "[LOG] #{message}"
  end
end

class Order
  include Loggable
end

order = Order.new
order.log("Order created")

=begin
Output:
[LOG] Order created

Notes:
- Loggable is a module, not a class — it can't be instantiated with .new,
  it only exists to be mixed into other classes.
- include Loggable inside the Order class body pulls log in as an
  instance method, available on any Order instance.
- order.log(...) works exactly as if log had been written directly inside
  the Order class — the including class can't tell the difference at the
  call site.
=end