Multi DNS and subdomain.

[eluser]Unknown[/eluser]
Hi everyone.
Sorry about my english is not good.

Example:
I have my url: localhost.com and user with subdomain is foo, link to foo's profile is localhost.com/foo. User foo want to dns he's domain to profile, foo.com = localhost.com/foo.

I use CI 2.x, HMVC, and template: http://williamsconcepts.com/ci/codeignit...rence.html. Currently, i make module for this:

modules
- admin
- user: for foo or someone.

my routes:
$route['^([a-zA-Z0-9]{3,30})(\/?)(.*?)$'] = "user/$3";

...

i need someone help me for solution, discuss about this problem. Thannks