Changed PHP mentoring url
Changed PHP mentoring url

Changed the url to .org instead of .com

Closes #81
heiglandreas/php.ug,php-ug/php.ug,heiglandreas/php.ug,heiglandreas/php.ug,php-ug/php.ug,php-ug/php.ug,php-ug/php.ug,heiglandreas/php.ug