Add zuul user to docker group

We are going to use containerized Openstack client
in test scripts. Adding zuul to the docker group
allows running docker command directly not using sudo.

Change-Id: Iee77e7f2b8801743f95535d31d0b909dcea50bf3

roles/deploy-env/defaults/main.yaml

@@ -26,6 +26,8 @@ kubeadm:
   service_cidr: "10.96.0.0/16"
 docker:
   root_path: /var/lib/docker
+docker_users:
+  - zuul
 containerd:
   root_path: /var/lib/containerd
 loopback_setup: false

roles/deploy-env/tasks/containerd.yaml

@@ -70,6 +70,10 @@
     src: files/daemon.json
     dest: /etc/docker/daemon.json
 
+- name: Add users to docker group
+  command: "adduser {{ item }} docker"
+  loop: "{{ docker_users }}"
+
 - name: Restart docker
   service:
     name: docker