curr_tot can be a None object (Issue #33 comment section, or https://…

…cloud.githubusercontent.com/assets/11442383/22823308/5ce383ca-efc6-11e6-81fb-c5d9641ca928.PNG)

manage_room/consumers.py

@@ -78,7 +78,7 @@ def room_leave(message):
     })
 
     curr_tot = cache.get(message["room"])
-    if curr_tot < 2:
+    if curr_tot and curr_tot < 2:
         cache.expire(message["room"], timeout=0)
     else:
         cache.set(message["room"], curr_tot - 1, timeout=7200)