custom URL mappings in codeigniter like redmine?

[eluser]WarDoGG[/eluser]
So redmine has a very peculiar url mapping style that i observed :

Code:

http://demo.redmine.org/projects/<project-name>/controller/action

samples :

Code:

http://demo.redmine.org/projects/produto/activity
http://demo.redmine.org/projects/produto/issues/new
http://demo.redmine.org/projects/produto/issues/gantt
http://demo.redmine.org/projects/produto/files

and the url changes as the project changes.

how do i do this in codeigniter ? I'm thinking it can be done with routes.php but so far i'm not able to get anywhere.

Looking for any help. Thanks.