feat(docker): add Docker Compose for PostgreSQL service

compose.yml

@@ -0,0 +1,18 @@
+volumes:
+  postgres_data:
+
+services:
+  db:
+    image: postgres:17.4
+    container_name: casino-db
+    restart: unless-stopped
+    volumes:
+      - postgres_data:/var/lib/postgresql/data
+    environment:
+      POSTGRES_DB: postgresdb
+      POSTGRES_USER: postgres_user
+      POSTGRES_PASSWORD: postgres_pass
+    healthcheck:
+      test: "exit 0"
+    ports:
+      - "5432:5432"