version: '2'
services:
  app:
    build:
      context: ./
      dockerfile: ./laravel/app.dockerfile
    working_dir: /var/www
    volumes:
      - ./:var/www
    environment:
      - "DB_PORT=3306"
      - "DB_HOST=database"
  web:
    build:
      context: ./
      dockerfile: ./nginx/web.dockerfile
    working_dir: /var/www
    volumes_from:
      - app
    ports:
      - 8080:80
  database:
    image: mysql:5.6
    volumes:
      - dbdata:/var/lib/mysql
    environment:
      - "MYSQL_DATABASE=homestead"
      - "MYSQL_USER=homestead"
      - "MYSQL_PASSWORD=secret"
      - "MYSQL_ROOT_PASSWORD=secret"
    ports:
      - "33061:3306"
volumes:
  dbdata:
--------------
FileStructure
docker-compose.yml
laravel
    app.dockerfile
nginx
    web.dockerfile
---------------
Error Message

Philipps-MBP:my-site philipp$ docker-compose up
mysite_database_1 is up-to-date
Creating mysite_app_1 ...
Creating mysite_app_1 ... error

ERROR: for mysite_app_1  Cannot create container for service app: invalid volume spec "var/www": invalid volume specification: 'var/www': invalid mount config for type "volume": invalid mount path: 'var/www' mount path must be absolute

ERROR: for app  Cannot create container for service app: invalid volume spec "var/www": invalid volume specification: 'var/www': invalid mount config for type "volume": invalid mount path: 'var/www' mount path must be absolute
ERROR: Encountered errors while bringing up the project.