find autoloader

$requireAutoloader = function() {
    $autoloaderLocations = [
        __DIR__ . '/../../autoload.php',
        __DIR__ . '/../vendor/autoload.php',
        __DIR__ . '/vendor/autoload.php'
    ];
    foreach($autoloaderLocations as $location) {
        if(is_file($location)) {
            require_once $location;
            return;
        }
    }
    fprintf(STDERR, 'You must set up the project dependencies using `composer install`' . PHP_EOL);
    fprintf(STDERR, "See https://getcomposer.org/download/ for instructions on installing Composer" . PHP_EOL);

    exit(1); // General error.
};
$requireAutoloader();