add field to the user registration (back-office)

begin:vcard
fn:Issolah mohamed
n:mohamed;Issolah
email;internet:isso.moh@gmail.com
version:2.1
end:vcard

Hey,

So I create a module slider to manage a banner of site.

The banner depend of the country choosed by front office user in site (user is not registred).

But in the back-office, this modules muste be manage by user depend on her country

Ex:

    I have some user:
            --> marc: montreal (manage only banner of montreal)
            --> houda: algeria   (manage only banner of algeria)
            ..etc

So I muste add field country in 'add django user' ==> if montreal user modify the modules, the modification take  effect in montreal banner.

How Can I add the field in back office registration ??

Thank and sorry for my english ^^
    

--  Issolah mohamed