Fatal error: Uncaught Error: Class 'Symfony\Component\HttpKernel\DependencyInjection\Extension' not found in /home/benjamincb/demos/acdg-site/vendor/contao/installation-bundle/src/DependencyInjection/ContaoInstallationExtension.php:20 Stack trace: #0 {main} thrown in /home/benjamincb/demos/acdg-site/vendor/contao/installation-bundle/src/DependencyInjection/ContaoInstallationExtension.php on line 20