Add a link to the changelog

docs/releases.rst

@@ -28,7 +28,7 @@ the main frontend container and terminates all connections, performing
 TLS and authentication directly. Letsencrypt support is now more complete,
 with various TLS "flavors" for all kinds of setup.
 
-More details about the changes are available in the changelog, and this
+More details about the changes are available in the `changelog`_, and this
 release will be followed by a short-term upgrade including some more features
 and bug fixes.
 
@@ -60,6 +60,8 @@ you would prefer the server IP address not be included anywhere (we do not log
 it, but our hosting provider might). This can be accomplished in the ``.env``
 file directly.
 
+.. _`changelog`: https://github.com/Mailu/Mailu/blob/master/CHANGELOG.md
+
 Mailu 1.3 - 2016-11-06
 ----------------------