Start at your ILIAS root directory
mkdir -p Customizing/global/plugins/Services/Cron/CronHook
cd Customizing/global/plugins/Services/Cron/CronHook
git clone [email protected]:tomaszkolonko/CleanUpSessions.git
cd CleanUpSessions
composer install
If you run composer from vagrant box, remember to run it as user www-data.
sudo -u www-data composer install