Add ntfy role

Installs and configures the ntfysh server to enable notifications.

roles/ntfy/templates/docker-stack.yml.j2

@@ -0,0 +1,25 @@
+version: '3.4'
+
+services:
+  app:
+    image: "{{ stack_image }}:{{ ntfy_version }}"
+    healthcheck:
+      test: ["CMD", "wget", "--spider", "-q", "localhost"]
+      interval: 1m
+      timeout: 10s
+      retries: 3
+      start_period: 1m
+    volumes:
+      - "{{ ntfy_upstream_file_dir }}/server.yml:/etc/ntfy/server.yml"
+      - cache:/var/cache/ntfy
+    networks:
+      - "{{ docker_swarm_public_network_name }}"
+
+volumes:
+  cache:
+
+networks:
+  "{{ docker_swarm_public_network_name }}":
+    external: true
+
+