There is a default option wich allow user to use Paypal for upgrade, but I would like to use something else called Starpass.
I know that I will have to create a PHP page when the codes they entered on the Starpass script are good to move my users to a certain "usergroup". Else, there is a default error.php page.
The question is, how could I make this PHP page to add my users who paid to another usergroup? Like, how the code will look?
This is a basic question I think, but i'm totally noob with that.
Thank you in advance.