howToIncludeAutoload.php

<?php

require_once realpath(
        dirname($_SERVER['SCRIPT_FILENAME'])
        . DIRECTORY_SEPARATOR
        . str_repeat(
                '..' . DIRECTORY_SEPARATOR,
                substr_count(
                    preg_replace('#^./#', '', $_SERVER['SCRIPT_FILENAME']),
                    DIRECTORY_SEPARATOR
                ))) . '/vendor/autoload.php';