lib/metro/scenes.rb
def add(scene)
      all_scenes_for(scene).each { |scene| scenes_hash[scene.scene_name] = scene.to_s }
    end
def add(scene)
      all_scenes_for(scene).each { |scene| scenes_hash[scene.scene_name] = scene.to_s }
    end
Add a scene to the hash of scenes with the scene name of the scene as the key
 to retrieving this scene.

 @param [Scene] scene the scene to be added to the hash of Scenes.