[fw-mvc] Custom Index Controller

Does anyone know how to tweek the default IndexController so that the
following URL displays a users profile. Currently I get the undefined
controller error.

http://www.mywebsite.com/123

I can get it to work if do the following
http://www.mywebsite.com/profile/123 but the current website displays
the profiles of its users using the first URL.

Anyone got any suggestions on how to best go about getting this working.

Thanks
Lionel Morrison