Docker – wordpress deployed on Digital Ocean Droplet – where is the wp-content?

Testing the Docker eco-system, I deployed my containers with docker-compose on a Digital Ocean droplet (created with docker-machine..) it’s running fine

the docker-compose.yml file is quite simple, using standard images

web:
    image: wordpress
    links:
     - mysql
    environment:
     - WORDPRESS_DB_PASSWORD=password
    ports:
     - "80:80"
    working_dir: /var/www/html
    volumes:
      - wp-content/:/var/www/html/wp-content
mysql:
    image: mysql:5.7
    environment:
     - MYSQL_ROOT_PASSWORD=password
     - MYSQL_DATABASE=wordpress

I can easily query the droplet url in my browser.

When I ssh into the droplet, I am searching for the wp-content folder in the droplet host, which is mounted as /usr/www/html/wp-content but I cannot find it… also the /var/www/html directory is empty… but the wordpress container is running

Where am I wrong ?