Use named volume for database

docker-compose.yml

@@ -40,10 +40,13 @@ services:
     env_file: db.env
     image: postgres:alpine
     volumes:
-      - /opaque_database:/var/lib/postgresql/data
+      - db:/var/lib/postgresql/data
   redis:
     deploy:
       placement:
         constraints:
           - node.role == manager
     image: redis:alpine
+
+volumes:
+  db: