userns; Document per user per user namespace limits.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
diff --git a/Documentation/sysctl/README b/Documentation/sysctl/README
index 8c3306e..91f54ff 100644
--- a/Documentation/sysctl/README
+++ b/Documentation/sysctl/README
@@ -69,6 +69,7 @@
 sunrpc/		SUN Remote Procedure Call (NFS)
 vm/		memory management tuning
 		buffer and cache management
+user/		Per user per user namespace limits
 
 These are the subdirs I have on my system. There might be more
 or other subdirs in another setup. If you see another dir, I'd