diff --git a/app/serializers/rest/promotion_serializer.rb b/app/serializers/rest/promotion_serializer.rb
index 3661765c..ad844d39 100644
--- a/app/serializers/rest/promotion_serializer.rb
+++ b/app/serializers/rest/promotion_serializer.rb
@@ -2,4 +2,8 @@
 
 class REST::PromotionSerializer < ActiveModel::Serializer
   attributes :status_id, :timeline_id, :position
+
+  def status_id
+    object.status_id.to_s
+  end
 end