README: update documentation section
Change-Id: I3320dc5eb3d183a18c2bd2fe3139f729978ea2a1
diff --git a/README.md b/README.md
index 1f14628..98a03d7 100644
--- a/README.md
+++ b/README.md
@@ -27,9 +27,10 @@
Documentation
-------------
-There currently is no other documentation other than the wiki on the
-homepage. It would be great if somebody would work towards a user
-manual that can become part of the osmo-gsm-manuals project.
+The user manual and VTY reference are optionally built in PDF form
+as part of the build process. Find pre-rendered versions here:
+
+https://ftp.osmocom.org/docs/osmo-ggsn/master/
Mailing List
------------