CraftVariable.php

class Project_Twig_Extension extends Twig_Extension implements Twig_Extension_GlobalsInterface
{
    public function getGlobals()
    {
        return array(
            'craft' => new \craft\web\twig\variables\CraftVariable(),
            'entry' => new \craft\elements\Entry(),
            'asset' => new \craft\elements\Asset(),
            'category' => new \craft\elements\Category(),
            'currentUser' => new \craft\elements\User(),
        );
    }
}