[N8N-4265] Improve docker compose setup with postgres (#3369)

* persist postgres data using docker volumes

* persist n8n data using docker volumes instead of writing to the host filesystem

* wait for postgres to be actually ready before starting the server

* run web server and workers as separate containers

* create a new `withPostgresAndWorker` example

docker/compose/withPostgresAndWorker/docker-compose.yml

@@ -0,0 +1,77 @@
+version: '3.8'
+
+volumes:
+  db_storage:
+  n8n_storage:
+  redis_storage:
+
+x-shared: &shared
+  restart: always
+  environment:
+    - DB_TYPE=postgresdb
+    - DB_POSTGRESDB_HOST=postgres
+    - DB_POSTGRESDB_PORT=5432
+    - DB_POSTGRESDB_DATABASE=${POSTGRES_DB}
+    - DB_POSTGRESDB_USER=${POSTGRES_NON_ROOT_USER}
+    - DB_POSTGRESDB_PASSWORD=${POSTGRES_NON_ROOT_PASSWORD}
+    - EXECUTIONS_MODE=queue
+    - QUEUE_BULL_REDIS_HOST=redis
+    - QUEUE_HEALTH_CHECK_ACTIVE=true
+    - N8N_BASIC_AUTH_ACTIVE=true
+    - N8N_BASIC_AUTH_USER
+    - N8N_BASIC_AUTH_PASSWORD
+  links:
+    - postgres
+    - redis
+  volumes:
+    - n8n_storage:/home/node/
+  depends_on:
+    redis:
+      condition: service_healthy
+    postgres:
+      condition: service_healthy
+
+
+services:
+  postgres:
+    image: postgres:11
+    restart: always
+    environment:
+      - POSTGRES_USER
+      - POSTGRES_PASSWORD
+      - POSTGRES_DB
+      - POSTGRES_NON_ROOT_USER
+      - POSTGRES_NON_ROOT_PASSWORD
+    volumes:
+      - db_storage:/var/lib/postgresql/data
+      - ./init-data.sh:/docker-entrypoint-initdb.d/init-data.sh
+    healthcheck:
+      test: ["CMD-SHELL", "pg_isready -h localhost -U ${POSTGRES_USER} -d ${POSTGRES_DB}"]
+      interval: 5s
+      timeout: 5s
+      retries: 10
+
+  redis:
+    image: redis:6-alpine
+    restart: always
+    volumes:
+      - redis_storage:/data
+    healthcheck:
+      test: ["CMD", "redis-cli", "ping"]
+      interval: 5s
+      timeout: 5s
+      retries: 10
+
+  n8n:
+    <<: *shared
+    image: n8nio/n8n
+    command: /bin/sh -c "n8n start --tunnel"
+    ports:
+      - 5678:5678
+
+  n8n-worker:
+    <<: *shared
+    image: n8nio/n8n
+    command: /bin/sh -c "sleep 5; n8n worker"
+    depends_on:
+      - n8n