fix: build nginx from Dockerfile instead of volume mount

docker-compose.yml

@@ -96,12 +96,10 @@ services:
       - backend
 
   nginx:
-    image: nginx:alpine
+    build: ./nginx
     restart: unless-stopped
     ports:
       - "8091:80"
-    volumes:
-      - ./nginx/nginx.conf:/etc/nginx/nginx.conf:ro
     depends_on:
       - backend
       - frontend