Spatie\Backup\Tasks\Backup\Manifest::addFiles PHP Method

    public function addFiles($filePaths) : Manifest
    {
        if (is_string($filePaths)) {
            $filePaths = [$filePaths];
        }
        foreach ($filePaths as $filePath) {
            if (!empty($filePath)) {
                file_put_contents($this->manifestPath, $filePath . PHP_EOL, FILE_APPEND);
            }
        }
        return $this;
    }