Adding .gitlab-ci.yml to our example project

We've added tests to our ROT13Formatter project, but now we need to get those tests to be automatically executed in GitLab (either GitLab.com or our own hosted instance). To do this, let's create a file called .gitlab-ci.yml in our project and add the following to it:

before_script:
  - apt-get update -qq && DEBIAN_FRONTEND=noninteractive apt-get install -y -qq ca-certificates git php php-xml
  - php -r "copy('https://getcomposer.org/installer', 'composer-setup.php');"
  - php composer-setup.php
  - php composer.phar install

phpunit:
  script:
    - vendor/bin/phpunit tests/ROT13FormatterTest

This exact file was discussed in the previous section, so we know that it simply executes a series of commands to configure the Runner and then runs one task that executes our tests. Now save, commit, and...