App\Http\Controllers\TournamentsController::register PHP Method

    public function register($id)
    {
        $tournament = Tournament::findOrFail($id);
        $user = Auth::user();
        if (!$tournament->isRegistrationOpen()) {
            return error_popup('registrations are closed!');
        }
        if (!$tournament->isValidRank($user)) {
            return error_popup('invalid rank!');
        }
        $tournament->register($user);
        return ujs_redirect("/tournaments/{$id}");
    }