Ubuntu 17.04 (will be released and a week or so) uses systemd-resolved instead dnsmasq, so would be good to enable support. Even a few people will install 17.04 on a Raspberry Pi, Ubuntu 18.04 LTS will use systemd-resolved too, and a lots of people will migrate (because will be the newest LTS release).
We are currently quite busy and will definitely look into adding support for Ubuntu 17.04 (at least on x86 hardware) in the upcoming 3.0 release. However, it is not yet released and the users should know that for Pi-hole v2.X we do not list this OS as officially supported.
Have you already tested it in combination with Pi-hole (I think there is only a beta2 available right now)? If so, can you describe what is not working properly (if anything)?
Ubuntu 17.04 is long gone and Pi-hole incorporates dnsmasq now.
Closing as out-of-scope.