A Docker Compose file that uses wait

docker-compose.yaml

version: '3.6'
services:
    database:
        image: postgres
        environment:
            - POSTGRES_PASSWORD=testing
            - POSTGRES_USER=testing
            - POSTGRES_DB=testing
        ports:
            - 5432
        expose:
            - 5432
        networks:
            - testing-network

    redis:
        image: redis
        ports:
            - 6379
        expose:
            - 6379
        networks:
            - testing-network

    backend:
        build:
            context: ../../../backend/
            dockerfile: $PWD/Dockerfile
        ports:
            - 3000
        environment:
            - DB_USERNAME=testing
            - DB_PASSWORD=testing
            - DB_DATABASE=testing
            - DB_HOST=database
            - REDIS_HOST=redis
            - WAIT_HOSTS: database:3306, redis:6379
            - WAIT_HOSTS_TIMEOUT: 300
        depends_on:
            - database
            - redis
        networks:
            - testing-network

networks:
    testing-network