[Rails] How to add an after_save callback on runtime on a particular instance

class User < AR
end

user = User.new

Let's say that I have a user instance with me. After this record is
saved I want an after_save callback which would print the id of the
record.
The only catch is that I am not allowed to change the User class. How
can I accomplish my goal? Is that even possible to add an after_save
callback on a particular instance object. Any metaprogramming hack.
I'm sure ruby does provide some tool.

This would be a trivial issue if I were allowed to change the User
class but I am not.

--
You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group.
To post to this group, send email to rubyonrails-talk@googlegroups.com.
To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe@googlegroups.com.
For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.