Design Pattern: Observer and Podcasts

podcast_sub.rb

class Podcast
  attr_reader :episodes, :subscribers
  
  def initialize()
    @episodes = []
    @subscribers = []
  end
  
  def add_subscriber(new_subscriber)
    subscribers << new_subscriber
  end
  
  def remove_subscriber(party_pooper)
    subscribers.delete(party_pooper)
  end
  
  def add_episode(new_episode)
    episodes << new_episode
    subscribers.each do |subscriber|
      subscriber.update(self)
    end
  end
end