Use Read The Docs for development docs

docs/.templates/page.html

@@ -12,7 +12,7 @@
         {% else %}
         <p>
         This document describes Celery {{ version }}. For development docs,
-        <a href="http://celery.github.com/celery/{{ pagename }}{{ file_suffix }}">go here</a>.
+        <a href="http://docs.celeryproject.org/en/master/{{ pagename }}{{ file_suffix }}">go here</a>.
         </p>
     {% endif %}