Sharepoint Provider Hosted App DNS Registration

Hi all I have been following the tutorial here to develop a sharepoint provider add in in sharepoint online.

http://www.sharepointnutsandbolts.com/2016/02/get-started-office-365-sharepoint-online-apps-add-ins-with-azure-vm.html

This works fine when i view it from my azure vm because there is a custom entry in my hosts file pointing to the local iis site.

If I wanted to deploy this to production what method would I use to register the custom host name for the iis website?

Is there something specific in Azure I can use?

many thanks in advance