Go to Godaddy and manage your domain. On the DNS Zone File Page set the A record to your elastic IP.
Create a CNAME document in the root of your repository. Mine looks like this:
That's the entire contents of the file, with the text flush left
On GitHub, go to setings. Look for the section on your GitHub pages.
That's the total contents of the file.
Go to your GoDaddy account.
Go to the domain page.
Choose to manage your domain.
In the DNS zone file page, set the CNAME alias for www to: