version: '2.4'
services:
  db:
    container_name: db
    image: postgres:12-alpine
    ...

  onlyoffice:
    container_name: onlyoffice
    image: onlyoffice/documentserver:latest
    ...
  redis:
    container_name: redis
    image: redis:alpine3.11
    ...
  app:
    container_name: app
    image: nextcloud:26
    depends_on:
      - db
      - redis
    links:
      - db
      - redis
      - onlyoffice
    ...