Let's say I have the following models:
User, has_many :messages, :topics
Forum, has_many :topics
Topic, belongs_to :user, has_many :messages
Message, belongs_to :user, :topic
How to tell both User and Topic, that a new Message has been created?
I can do: @user.messages << @message, but what to do to notify the
@topic? Is it possible to do that in a pretty manner?