README: Add link to instructions for publishing the docs

I was looking for these instructions in the README.md file and any other
file in the root folder, but they are in a file somewhere in the folder
structure where they are hard to find.

Signed-off-by: Edwin Kempin <ekempin@google.com>
Change-Id: I251a964a7434022499db3d935ee47c29abdf834e
diff --git a/README.md b/README.md
index bb1c499..ea959be 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,6 @@
 Homepage for [Gerrit Code Review][home].
 
 [home]: https://www.gerritcodereview.com/
+
+Instructions how to publish the Gerrit documentation can be found at:
+https://www.gerritcodereview.com/publishing.html