Show the account id in the user settings screen

This may help an administrator track down a particular user
account, as they can ask the user for the account id field
after they have logged into the site.

Signed-off-by: Shawn O. Pearce <sop@google.com>
diff --git a/Documentation/install.txt b/Documentation/install.txt
index 594861e..6a7ffd5 100644
--- a/Documentation/install.txt
+++ b/Documentation/install.txt
@@ -349,6 +349,10 @@
   );
 ====
 
+You can also get your `account_id` from the web UI, under Settings,
+if you don't want to use a SELECT subquery above, or your email
+address wasn't prefilled automatically.
+
 Group memberships are cached, so you need to either restart Gerrit,
 or try flushing the caches over SSH.