Add guide on how to edit site, various tweaks.

Change-Id: Iadb5074e130d4a42b2af123fa405e9fc21a14aed
Reviewed-on: https://asterix-gerrit.ics.uci.edu/541
Reviewed-by: Till Westmann <tillw@apache.org>
diff --git a/_includes/nav_header.html b/_includes/nav_header.html
index 5123fab..28db61c 100644
--- a/_includes/nav_header.html
+++ b/_includes/nav_header.html
@@ -38,6 +38,7 @@
                   <li class="divider"></li>
                   <li class="dropdown-header">For Committers</li>
                   <li><a href="{{ site.url }}pushing.html">Pushing changes</a></li>
+                  <li><a href="{{ site.url }}site.html">Editing this site</a></li>
                 </ul>
               </li>
             </ul>