[Radiant] Alias Page Extension

[Daniel Sheppard]

> True, and subclasses_of is a bit of a slow operation (iterates over  
> every class in ObjectSpace).  Might be better to have a registration  
> method instead.
> 
> class MyNotFoundPage < Page
>     not_found_class
> end

Are you sure that's what subclasses_of does? I know that there's definitely a method on ActiveRecord::Base that keeps track of
subclasses as their created - maybe it's called something else - descendants maybe? - I can't remember, but I'm pretty sure it
exists.

Dan.