def build_draft_uploads
        self.attributes.keys.each do |key|
          if (self.respond_to?(key) &&
              self.send(key).is_a?(CarrierWave::Uploader::Base) &&
              self.send(key).file)
            self.draft.draft_uploads << build_draft_upload(key)
          end
        end
      end
def build_draft_uploads
        self.attributes.keys.each do |key|
          if (self.respond_to?(key) &&
              self.send(key).is_a?(CarrierWave::Uploader::Base) &&
              self.send(key).file)
            self.draft.draft_uploads << build_draft_upload(key)
          end
        end
      end
Loop through and create DraftUpload objects for any Carrierwave
 uploaders mounted on this draftable object.

 @param [Hash] attrs the attributes to loop through
 @return [Array<DraftUpload>] an array of unsaved DraftUpload objects.