add media url to schema

store_back/apps/goods/schema.py

@@ -22,8 +22,8 @@ class ImageType(graphene.ObjectType):
         return self._id
 
     def resolve_url(self,info):
-        print(settings.MEDIA_URL + self.url)
-        return settings.MEDIA_URL + self.url
+        print(settings.MEDIA_URL + str(self.url))
+        return settings.MEDIA_URL + str(self.url)
 
 
 class ImageInput(graphene.InputObjectType):