---
version: "3"
services:
  instance:
    build:
      context: .
    container_name: autossl-synology
    hostname: autossl-synology

    env_file: env/instance.env
    volumes:
      - /usr/syno/etc/ssl/ssl.crt:/usr/syno/etc/ssl/ssl.crt
      - /usr/syno/etc/ssl/ssl.key:/usr/syno/etc/ssl/ssl.key
...