chore: add new example

examples/voting-app/docker-compose.yml

@@ -0,0 +1,89 @@
+# https://github.com/docker/labs/blob/master/beginner/chapters/votingapp.md
+
+version: "3.9"
+
+services:
+  redis:
+    image: redis:alpine
+    ports:
+      - "6379"
+    networks:
+      - frontend
+    deploy:
+      replicas: 2
+      update_config:
+        parallelism: 2
+        delay: 10s
+      restart_policy:
+        condition: on-failure
+  db:
+    image: postgres:9.4
+    volumes:
+      - db-data:/var/lib/postgresql/data
+    networks:
+      - backend
+    deploy:
+      placement:
+        constraints: [node.role == manager]
+  vote:
+    image: dockersamples/examplevotingapp_vote:before
+    ports:
+      - 5000:80
+    networks:
+      - frontend
+    depends_on:
+      - redis
+    deploy:
+      replicas: 2
+      update_config:
+        parallelism: 2
+      restart_policy:
+        condition: on-failure
+  result:
+    image: dockersamples/examplevotingapp_result:before
+    ports:
+      - 5001:80
+    networks:
+      - backend
+    depends_on:
+      - db
+    deploy:
+      replicas: 1
+      update_config:
+        parallelism: 2
+        delay: 10s
+      restart_policy:
+        condition: on-failure
+  worker:
+    image: dockersamples/examplevotingapp_worker
+    networks:
+      - frontend
+      - backend
+    deploy:
+      mode: replicated
+      replicas: 1
+      labels: [APP=VOTING]
+      restart_policy:
+        condition: on-failure
+        delay: 10s
+        max_attempts: 3
+        window: 120s
+      placement:
+        constraints: [node.role == manager]
+  visualizer:
+    image: dockersamples/visualizer
+    ports:
+      - "8080:8080"
+    stop_grace_period: 1m30s
+    volumes:
+      - /var/run/docker.sock:/var/run/docker.sock
+    deploy:
+      placement:
+        constraints: [node.role == manager]
+
+networks:
+  frontend:
+  backend:
+
+volumes:
+  db-data: