added postgres db

docker-compose.yml

@@ -28,5 +28,14 @@ services:
     restart: unless-stopped
     ports:
       - 8080:8080
-    volumes:
+
-      - ./backend:/app
+  db:
+    image: postgres:16
+    container_name: db
+    restart: unless-stopped
+    environment:
+      POSTGRES_USER: postgres
+      POSTGRES_PASSWORD: password
+      POSTGRES_DB: simplebackend
+    ports:
+      - 5432:5432