Updated change-log.

Signed-off-by: Taylor Otwell <taylorotwell@gmail.com>

changes.txt

@@ -15,4 +15,5 @@ Changes for 3.1:
 	- Removed error.display config options.
 	- Added foreign key support to schema builder.
 	- Postgres "unique" indexes are now added with ADD CONSTRAINT
-	- Added "Event::until" method.
+	- Added "Event::until" method.
+	- Added "memory" cache and session drivers.