add reference to dc13 talk to docs

Signed-off-by: martin f. krafft <madduck@madduck.net>
diff --git a/doc/source/index.rst b/doc/source/index.rst
index 44b02cb..226b7da 100644
--- a/doc/source/index.rst
+++ b/doc/source/index.rst
@@ -46,6 +46,7 @@
    concepts
    operations
    usage
+   refs
    manpage
    configfile
    salt