Allow users to subscribe to community chat topics

Dockers/socket-broker/README.md

@@ -19,7 +19,8 @@ Frontend / mobile clients
         │  Socket.IO (connection token + topic token)
         ▼
 Socket broker  ── rooms: user/{uuid}/notifications
-        ▲                 event/{slug}/ticket_statistics
+        ▲                 community/user/{uuid}
+        │                 event/{slug}/ticket_statistics
         │  POST /publish (API key)
 Laravel backend
 ```
@@ -74,7 +75,7 @@ const socket = io("https://bram-sockets.comedykit.be", {
 });
 ```
 
-A user may always subscribe to `user/{their-own-id}/notifications`. Any other topic requires a topic token whose `sub` matches the connection subject and whose `topic` matches the subscription exactly.
+A user may always subscribe to `user/{their-own-id}/notifications` and `community/user/{their-own-id}`. Any other topic requires a topic token whose `sub` matches the connection subject and whose `topic` matches the subscription exactly.
 
 ## WebSocket API