update docker compose example

docker-compose.example.yml

@@ -0,0 +1,23 @@
+services:
+  web:
+    image: docker.arimelody.me/arimelody.me:latest
+    build: .
+    ports:
+      - 8080:8080
+    volumes:
+      - ./uploads:/app/uploads
+      - ./config.toml:/app/config.toml
+    environment:
+      ARIMELODY_CONFIG: config.toml
+  db:
+    image: postgres:16.1-alpine3.18
+    volumes:
+      - arimelody-db:/var/lib/postgresql/data
+    environment:
+      POSTGRES_DB: # your database name here!
+      POSTGRES_USER: # your database user here!
+      POSTGRES_PASSWORD: # your database password here!
+
+volumes:
+  arimelody-db:
+    external: true