运行docker-compose命令，如build和up。
然而，当我尝试连接Docker与VS代码我得到这个错误：

The Compose file is invalid because:
Service your-service-name-here has neither an image nor a build context specified. At least one must be provided.

这是合成文件：

version: '3'
services:
  db:
    image: postgres
    ports:
      - "5432:5432"

  web:
    build: .
    command: bin/rails server --port 3000 --binding 0.0.0.0
    ports:
      - "3000:3000"
    links:
      - db
    volumes:
      - .:/myapp