Note in schema version.

Author: clokep

synapse/storage/schema/__init__.py

@@ -66,10 +66,11 @@
       updated.
 
 Changes in SCHEMA_VERSION = 70:
-    - event_reference_hashes is no longer written to.
+    - event_reference_hashes is no longer written to. 
 
 Changes in SCHEMA_VERSION = 71:
     - event_edges.room_id is no longer read from.
+    - Tables related to groups are no longer accessed.
 """