Orderable concern rails 3

example_controller.rb

class Admin::SizesController < Admin::AdminController
  include OrderableController
end

example_model.rb

class Size < ActiveRecord::Base
  include Orderable
end

orderable.rb

module Orderable
  extend ActiveSupport::Concern
  
  included do
    default_scope { order("`order` ASC") }
    after_initialize :max_order!, :if => Proc.new {|row| row.order == 0}
  end

  module ClassMethods
    def sort(ids)
      order = 1
      ids.each do |id|
        update id, :order => order
        order += 1
      end
    end
  end

  private 

  def max_order!
    self.order = self.class.name.constantize.maximum(:order).to_i + 1
  end
end

orderable_controller.rb

module OrderableController
  def sort
    model    = self.class.name.split("::").last.gsub(/Controller/, '').singularize
    var_name = model.underscore
    sequence = params[:order].gsub(/#{var_name}\[\]=/, '').split("&")
    model.constantize.sort sequence
    render nothing: true
  end
end