update cron

Cron-Jobs.md

@@ -11,13 +11,13 @@ crontab -e
 this will run every 4 hours
 
 ```bash
-0 */4 * * * /usr/bin/php -f /path/to/phpmixbill/system/cron.php
+0 */4 * * * cd /path/to/phpnuxbill/system/ && php -f cron.php
 ```
 
 if you create hourly voucher, maybe you need to run every 5 minutes
 
 ```bash
-*/5 * * * * /usr/bin/php -f /path/to/phpmixbill/system/cron.php
+*/5 * * * * cd /path/to/phpnuxbill/system && php -f cron.php
 ```
 
 another example [crontab.guru](https://crontab.guru/examples.html)