docker-compose config file with mysql and phpmyadmin

docker-compose.yml

version: "2"
services:
    db:
        image: mysql
        ports: 
            - "3306:3306"
        environment:
            MYSQL_DATABASE: myDb
            MYSQL_USER: user
            MYSQL_PASSWORD: test
            MYSQL_ROOT_PASSWORD: test
    phpmyadmin:
        image: phpmyadmin/phpmyadmin
        links: 
            - db:db
        ports:
            - 8000:80
        environment:
            MYSQL_USER: user
            MYSQL_PASSWORD: test
            MYSQL_ROOT_PASSWORD: test
        volumes:
            - /sessions