If during the install I put the ip address of my machine for www.domain.com

123.123.23.123  (Not real)

How do I go back later and set it to the subdomain I allocated for it from my hosting service?blah.blahblah.com

I found a file at /var/www/canvas/config/domain.yml

But changing the production>domain: to blah.blahblah.com didnt work. After reboot I tried navigating to the url blah.blahblah.com on a different machine and was only greeted with my hosting service's placeholder page.