add message and comment

announcement/urls/oj.py

@@ -1,8 +1,7 @@
 from django.urls import re_path as url
 
-from ..views.oj import AnnouncementAPI, MessageAPI
+from ..views.oj import AnnouncementAPI
 
 urlpatterns = [
     url(r"^announcement/?$", AnnouncementAPI.as_view(), name="announcement_api"),
-    url(r"^message/?$", MessageAPI.as_view(), name="message_api"),
 ]