[development] Pathauto scaleability - path column in node / user table

[Karthik]

> But this also leaves out 'user' and any othe rnon-node object that may
> want URLs of this nature.

Then we need a 'realm'/'type' which is also indexed. Is the
alternative to add a path varchar field to the node, user, foo and bar
tables? Or even a path ID?

-K