I'm working on a site that is running Craft v2 and also has an installation of Simple Machines Forum (SMF). This has been fine using the approach outlined in this answer, i.e.
$craft = include '/craft/app/bootstrap.php'; echo $craft->templates->render('includes/nav');
Now the site is being upgraded to v3 and this isn't working anymore. I've tried this:
$craft = include '/craft/vendor/craftcms/cms/bootstrap/web.php'; echo Craft::$app->getView()->renderTemplate('includes/nav');
but with that I get:
Uncaught Error: Class 'craft\services\Config' not found in /craft/vendor/craftcms/cms/bootstrap/bootstrap.php on line 165
What else is missing to get this to work for Craft 3?