Passing current_user into the model

gistfile1.rb

#Aplication Controller
before_filter :define_current_user

def define_current_user
  User.current_user = current_user
end

#User.rb (model)
class User
  class << self
    attr_accessor :current_user	
  end
end

#Account.rb (target model)
fires :updated,
      on:    :update,	
      actor: Proc.new { User.current_user },
      data:  :changes,	
      if: Proc.new { | acc | !acc.changes.blank? && acc.changes[:cancellation_code].blank? }