Update CNAME to association.drupalcampmontreal.com

At the moment only *.drupalcampmontreal.com redirects Acquia cloud, while association.drupalcampmontreal.com CNAME drupalmontreal.github.io (Github Pages).

This pull request will make the site visible.
Merge pull request #1 from dergachev/CNAME

Update CNAME to association.drupalcampmontreal.com (because of http://instantclick.io/github-pages-and-apex-domains)