Optional list of users to add to docker group

roles/docker/tasks/main.yml

@@ -41,13 +41,13 @@
     state: present
     update_cache: true
 
-- name: Add user to docker group
+- name: Add users to docker group
   user:
-    name: "{{ docker_user }}"
+    name: "{{ item }}"
     groups: docker
-    skeleton: /etc/skel
-    shell: /bin/bash
     append: true
+  loop: "{{ docker_users }}"
+  when: users is defined
 
 - name: Install docker-compose
   script: install-compose.sh