How do I replicate the result of this dns-sd command?

[ilpoldo]

dns-sd -P my_new_app _http local 80 my_new_app.local <my.dev.machine.ip>

You know, for the developers!
The commands is designed to register a proxy service, it does so by adding to the service this record in the mDNS soup:
my_new_app.local. 10 IN A <my.dev.machine.ip>

Let's assume you have the usual passenger setup with virtual hosts on your dev machine; this means that from the local network other browsers (like the one in your phone) can hit your dev app.
I just think that the A record is a bit brittle and not very mDSN like. I'm trying to figure out how to use this gem to do the same thing and eventually replace the A record with one or two CNAME.

The goal is to make something like:
my_new_app.local. 10 IN CNAME my_dev_book.local.

mobile.my_new_app.local. 10 IN CNAME my_dev_book.local.

My feeling is that a snippet that can achieve this inside this gem's example folder would prove really useful to many.