Rails Environment Based Behavior

gistfile1.rb

# app/models/user.rb
class User < ActiveRecord::Base
end

# lib/user_logger.rb
module UserLogger
  def self.included(mod)
    mod.send :after_create, :log_creation
  end

  protected
  def log_creation
    Log.new_user(self)
  end
end

# config/environments/production.rb
User.send(:include, UserLogger)