Forgive me if this is an obvious question. I am fairly new to docker and I am having trouble understanding the installation instructions here: https://hub.docker.com/_/composer/
I want to use PHP Composer in my Limesurvey docker image that was generated with the following docker-compose "yml" file:
limesurvey-md:
  image: mariadb
  restart: always
  ports:
    - "32805:3306"
  environment:
    MYSQL_DATABASE: limesurvey
    MYSQL_ROOT_PASSWORD: password
    MYSQL_USER: limesurvey
    MYSQL_PASSWORD: password
  volumes:
    - limesurvey-db:/var/lib/mysql
    - limesurvey-dblog:/var/log/mysql
    - limesurvey-dbetc:/etc/mysql
limesurvey:
  image: fjudith/limesurvey
  restart: always
  ports:
    - "32705:80"
  volumes:
    - limesurvey-upload:/var/www/html/upload
  links:
    - limesurvey-md:mysql
What do I need to add to my yml file to accomplish this? If it helps, there is a directory called "application" in the Limesurvey image:
 /var/www/html/application
And how do I give this composer a command while it is in the container? I am using Windows 10 and the docker container is running the default linux environment. fjudith's Limesurvey container is using the last 2.X branch of Limesurvey (the one right before 3.X) and it is running PHP 7.2