DependencyInjector.php

<?php
public function setUpServices()
{
      $this->services = [
          'twig.loader' =>[
              'class' => '\Twig_Loader_Filesystem',
              'arguments' => [__DIR__.'/views']
          ],
          'twig.templating' => [
              'class' => '\Twig_Environment',
              'arguments' => ['@twig.loader']
          ],
      ];
}