added facebook to communication channels

rowers/templates/email.html

@@ -68,6 +68,14 @@ Bug reports and feature requests can be done through our BitBucket page. Please
 </ul>
 </p>
 
+<h1>Facebook Group</h1>
+
+<p>We run a facebook group where you can post questions and report problems,
+  especially if you think the wider user community benefits from the answers.</p>
+<ul>
+  <li><a href="https://www.facebook.com/groups/rowsandall/">https://www.facebook.com/groups/rowsandall/</a></li>
+</ul>
+
 <h1>Twitter</h1>
 
 <p>You can also check me on Twitter:
@@ -79,4 +87,4 @@ When the site is down, this is the appropriate channel to look for apologies, up
 
 </div>
     {% endblock content %}
-  
+