Render devstack ansible roles via zuul-sphinx

Change-Id: Ie0db5bcfdacc2543488704fe4428b68910bd6bf1
diff --git a/doc/source/roles.rst b/doc/source/roles.rst
new file mode 100644
index 0000000..5baa1e4
--- /dev/null
+++ b/doc/source/roles.rst
@@ -0,0 +1,4 @@
+Roles
+=====
+
+.. zuul:autoroles::