Redirect to another URL

[eluser]jigen7[/eluser]
hi i got a this part of a code to my index in my user controller that redirects it to the login function but i want to do is redirect it to another url not within the site for example http://google.com and i cant find the way to do it can anyone help me through here thanks

Code:

function index()
    {
          redirect('user/login');
    }