add postgres examples

docker/docker-compose.yml

@@ -0,0 +1,19 @@
+services:
+  postgres:
+    image: postgres:15
+    restart: unless-stopped
+    environment:
+      POSTGRES_DB: appdb
+      POSTGRES_USER: appuser
+      POSTGRES_PASSWORD: changeme
+    ports:
+      - "5432:5432"
+    volumes:
+      - pg_data:/var/lib/postgresql/data
+    healthcheck:
+      test: ["CMD-SHELL", "pg_isready -U $$POSTGRES_USER -d $$POSTGRES_DB"]
+      interval: 3s
+      timeout: 3s
+      retries: 5
+volumes:
+  pg_data: