correctly reference the current user via 'ansible_env.USER' where needed

Author: tknerr

roles/docker/tasks/main.yml

@@ -17,7 +17,7 @@
 
 - name: Add VM user to 'docker' group
   user:
-    name: "{{ ansible_env.SUDO_USER }}"
+    name: "{{ ansible_env.USER }}"
     groups: docker
     append: yes
   become: yes