docker compose port

docker compose allow to expose port like this

ports (HOST:CONTAINER),

    version: "2"
    services:
        vahed98-gateway:
            image: vahed98-gateway
            environment:
                - SPRING_PROFILES_ACTIVE=prod,swagger
                - ZUUL_ROUTES_APP_URL= http://vahed98-smart-service:8082/app/
                - JHIPSTER_SLEEP=10 # gives time for the database to boot before the application
            ports:
                - 8080:80
            depends_on:
                - "vahed98-smart-service"