install php unit or other dependencies via docker composer

docker run --rm --interactive --tty \
--volume $PWD:/app \
composer <command>

configure php storm with remote interpreter

1. insert remote interpreter by using docker-compose

2. set path to text framework -> autoload: /var/www/vendor/autoload.php

3. set path to test framework -> phpunit.xml: /skeleton-php-cli/phpunit.xml