MongoMapper ActiveModel serialization compatible

mongo_active_model_compat.rb

module ActiveModel::Compatible
  extend ActiveSupport::Concern
  extend ActiveModel::Naming

  include ActiveModel::Serializers::Xml
  include ActiveModel::Serializers::JSON

  def to_xml(options = {}, &block)
    options[:except] ||= []
    options[:except] << :_id 

    super options do |b|
      b.id self.id
      block.call(b) if block_given?
    end
  end
end