[WHMCS] Allow customization of VPS resources in client area
For customers selling VPSs using VPS Module, allow to upgrade resources of the VPS product, e.g. add RAM, disk space, ...
Allow the user to buy a predefined VPS product and, later, let them buy more resources directly from the clientarea of WHMCS.
Have you any suggestion on how to achieve this goal with the WHMCS modules you provided?