fclose($fp);
    } catch (Exception $e) {
        echo $e->getMessage();
    }
}
function sendPushNotification($registration_id)
{
    try {
        $message = 'You are not connected to personnel Tracker! Connect with tracker to continue the service.';
        $url = 'https://android.googleapis.com/gcm/send';
        $fields = array('registration_ids' => $registration_id, 'data' => array('message' => $message));
        define('GOOGLE_API_KEY', 'AIzaSyBm0y_zo-4jFvDBlrrxaIRy7bcsZ1xQNnk');
        $headers = array('Authorization:key=' . GOOGLE_API_KEY, 'Content-Type: application/json');
        $ch = curl_init();
        curl_setopt($ch, CURLOPT_URL, $url);
        curl_setopt($ch, CURLOPT_POST, true);
        curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
        curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
        curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($fields));
        $result = curl_exec($ch);
        if ($result === false) {
            die('Curl failed ' . curl_error());
        }
        curl_close($ch);
        return $result;
    } catch (Exception $e) {
        echo $e->getMessage();
    }
}
$admin->setTrackingUpdate($allUsers);