Add slaves into jenkins stack

Change-Id: Ia9982513981d963a97a53e9ea90fcbae1fc202e7
diff --git a/docker/swarm/stack/jenkins/init.yml b/docker/swarm/stack/jenkins/init.yml
new file mode 100644
index 0000000..ab4f07e
--- /dev/null
+++ b/docker/swarm/stack/jenkins/init.yml
@@ -0,0 +1,3 @@
+classes:
+  - system.docker.swarm.stack.jenkins.master
+  - system.docker.swarm.stack.jenkins.slave