def translation_class
      @translation_class ||= begin
        klass = self.const_get(:Translation) rescue nil
        if klass.nil?
          klass = self.const_set(:Translation, Class.new(Mongoid::Globalize::DocumentTranslation))
        end
        klass.embedded_in name.underscore.gsub('/', '_')
        klass.translated_klass = self
        klass
      end
    end
def translation_class
      @translation_class ||= begin
        klass = self.const_get(:Translation) rescue nil
        if klass.nil?
          klass = self.const_set(:Translation, Class.new(Mongoid::Globalize::DocumentTranslation))
        end
        klass.embedded_in name.underscore.gsub('/', '_')
        klass.translated_klass = self
        klass
      end
    end
Returns translation class
 First use creates this class as subclass of document's class based on
 Mongoid::Globalize::DocumentTranslation, creates other side for embeded
 relationship.