admin修改username后update submissions；

problem id refresh api

contest/views/oj.py

@@ -16,7 +16,7 @@ class ContestAnnouncementListAPI(APIView):
     def get(self, request):
         contest_id = request.GET.get("contest_id")
         if not contest_id:
-            return self.error("Invalid parameter")
+            return self.error("Invalid parameter, contest_id is required")
         data = ContestAnnouncement.objects.select_related("created_by").filter(contest_id=contest_id, visible=True)
         max_id = request.GET.get("max_id")
         if max_id:
@@ -28,7 +28,7 @@ class ContestAPI(APIView):
     def get(self, request):
         id = request.GET.get("id")
         if not id:
-            return self.error("Invalid parameter")
+            return self.error("Invalid parameter, id is required")
         try:
             contest = Contest.objects.get(id=id)
             return self.success(ContestSerializer(contest).data)