How to setup MongoMapper Observer

I'm trying to create some mongo mapper observer. I found a class exit for that : http://rubydoc.info/gems/danielharan-mongo_mapper/0.6.5/MongoMapper/Observer

The question is how to activate them.

I create an app/observers/admin_observer.rb

class AdminObserver < MongoMa开发者_高级运维pper::Observer
 observe :admin # my admin model

 # call backs ...
end

The question now is how to active them ? The active record way is :

module MyApp
  class Application < Rails::Application
     config.active_record.observers = :admin
     # other config
  end
end

But with MongoMapper no active_record. Quite naive, I tried config.mongo_mapper.observers = :admin, but their is no observers in mongo_mapper configuration ...

I dunno what to try else and my google research didn't give me a clue.

That appears to be a really old, un-maintained fork of MongoMapper--using a 2-year-old gem is asking for trouble.

If you find it's really better to use an observer rather than just implement the callbacks directly in your model, your best bet may be to fork MongoMapper and add the functionality you want (MM's code is pretty clean), or better yet make a gem that extends MongoMapper with an observer functionality.