add pihole stack

ansible/roles/pihole/tasks/main.yml

@@ -0,0 +1,15 @@
+- name: Create working directory
+  file:
+    path: /srv/pihole
+    state: directory
+
+- name: Copy Docker stack file
+  template:
+    src: "{{ role_path }}/docker-stack.yml.j2"
+    dest: /srv/pihole/docker-stack.yml
+
+- name: Deploy Docker stack
+  docker_stack:
+    name: pihole
+    compose:
+      - /srv/pihole/docker-stack.yml