It's fairly easy and straight-forward to link your gitbook to a custom sub-domain (ex. http://gitbook.opensourcedharma.info), but it's a bit more complicated to link a gitbook to a root domain (ex. www.opensourcedharma.info).
Here we offer some instructions on linking your gitbook to a root domain, using iwantmyname.com, a standard domain registrar, and cloudflare, a company that offers various domain-related services. You can use other registrar services to do this, but in these instructions we'll only show you how to do this with iwantmyname.com. We haven't tested, or confirmed, this process on other registrars, so just be aware that this may not work exactly the same way on another service.