[Radiant] Minimal configuration for vhost_extension

[Wes Gamble]

 I have installed the vhost extension (with an eye to future expansion, 
but really just to easily install the crm extension).

Upon installation, of course, I have no sites configured.
What is the absolute minimum that I need to do to basically default my 
existing, singular site into a vhost-compatible site?

Thanks,
Wes