Remove class from url.

[eluser]Girgoo[/eluser]
Hi

I am new to codeigniter and have found it useful.
The URL should be example.com/class/function/ID as it sas in the documentation.
But what if i would like to have a url look like this?

example.com/username/article
example.com/John/dogs

The problem is that John is not a class.
Can i solve this with codeigniter?