[MOD/FIX] Update user list at the lowest level

I'll need to start defining a `diffs' system for sync. I have a decent
idea on how that could go(with 1 level of batching), but I'll need to
consider it some.

src/Room.c

@@ -1815,6 +1815,33 @@ RoomAddEventV1(Room *room, PduV1 pdu)
     /* TODO: Store DAG relationships, somehow.
      * Also keep track of PDU depth. */
 
+    if (StrEquals(pdu.type, "m.room.member"))
+    {
+        CommonID *id = UserIdParse(pdu.state_key, NULL);
+        User *user   = UserLock(room->db, id->local);
+        char *membership = JsonValueAsString(
+            HashMapGet(pdu.content, "membership")
+        );
+
+        if (StrEquals(membership, "join") && user)
+        {
+            UserAddJoin(user, room->id);
+        }
+        else if (StrEquals(membership, "invite") && user)
+        {
+            UserAddInvite(user, room->id);
+        }
+        else if ((StrEquals(membership, "leave") && user) ||
+                StrEquals(membership, "ban"))
+        {
+            UserRemoveInvite(user, room->id);
+            UserRemoveJoin(user, room->id);
+        }
+
+        UserIdFree(id);
+        UserUnlock(user);
+    }
+
     return true;
 }
 HashMap *
@@ -2015,6 +2042,7 @@ RoomSendInvite(User *sender, bool direct, char *user, Room *room)
     }
     ConfigLock(room->db, &conf);
     senderID = UserIdParse(UserGetName(sender), conf.serverName);
+    senderID->sigil = '@';
     senderStr = ParserRecomposeCommonID(*senderID);
     UserIdFree(senderID);