Calling class methods from included module

Hi,

I have these two ActiveRecord models: UserEvent and CoordinateEvent.

The models are extended with the module MapEvent. MapEvent includes some
class methods and some instance methods.

Now, I want both models to use ActiveRecord's serialize
(http://api.rubyonrails.org/classes/ActiveRecord/Base.html#M001984).

My MapEvent looks something like the following. I simply can't figure
where to put "serialize :column_name":

[code]
module MapEvent
  def self.included(base)
    base.extend(ClassMethods)
  end

  def a_method
  end

  module ClassMethods
    def another_method
    end
  end
end
[/code]

How do I call the serialize method from the above context?

An extra question:
Also, it suddenly hit me, that instead of a module I could write
MapEvent as a class that inherits from ActiveRecord instead of a module
- and then let UserEvent and CoordinateEvent inherit from MapEvent?
Would you recommend this? Generally speaking, when should you use
mixins/module and when you use inheritance?

Hope my questions are clear. Thanks in advance!