For [Design Patterns in Life and Ruby](https://medium.com/series/design-patterns-in-life-and-ruby-fcde31ba51a0/edit)

burger.rb

class Burger
  attr_reader :top_bun, :bottom_bun
  attr_accessor :stuffing

  def initialize(stuffing)
    @top_bun = TOP_BUN
    @stuffing = stuffing
    @bottom_bun = BOTTOM_BUN
  end

  def cook
    burger = []
    burger << top_bun.cook
    burger << stuffing.cook
    burger << bottom_bun.cook
    burger
  end
end