Task Scheduling : Laravel 5.3

I am following this tutorial to schedule a function every minute. Below is my code.

class Kernel extends ConsoleKernel
{
    protected $commands = [
        'App\Console\Commands\Inspire',
    ];

    protected function schedule(Schedule $schedule)
    {
        $schedule->call($this->WriteFile())->everyMinute();
    }

    protected function commands()
    {
        require base_path('routes/console.php');
    }

    private function WriteFile() {
        $myfile = fopen("newfile.txt", "w") or die("Unable to open file!");
        $txt = "John Doe\n";
        fwrite($myfile, $txt);
        fclose($myfile);
    }
}

I saw that the txt file is not showing the contents. i placed the txt file in public folder. Am I missing something?

via Chebli Mohamed