Can not add ActiveRecord callback by using class_eval method

Question

I have a User model, which includes module Staff:

class User < ActiveRecord::Base
  include Staff
  ...
end

I want to add an after_update callback to all the models that include this module:

module Staff
  def self.included(model)
    model.class_eval do
      after_update :callback
    end
  end

  private
  def callback
    ...
  end
end

I get a NoMethodError:

undefined method `after_update' for Object:Class

What am I doing wrong?

Answer 1

Solved! The problem was that I had another class including my module Staff, which was not an ActiveRecord model.