How to enable "www." for my google domain

I've recently bought a google domain for my website the naked domain is linked correctly to my website for example: http://domainname.com goes to my host space and loads my site. Although this works I can't seem to load the site when I type in http://ift.tt/1kSdBoW. Is there am extra step I need to take or is there something I need to activate on my domains DNS setting to make my site load when I add www.?