NOW THAT CODEIGNITER 4 HAS BEEN RELEASED, THIS PROJECT WILL NOT BE UPDATED ANYMORE. CI3 Fire Starter is a CodeIgniter3 skeleton application that includes jQuery and Twitter Bootstrap. It is intended to be light weight, minimalistic and not get in your way of building great CodeIgniter 3 applications.
CI 3 is supposed to have this handled in the $config['composer_autoload'] setting (https://www.codeigniter.com/user_guide/general/autoloader.html). I believe the article you referenced applies only to CI 2 or older. Closing.