I do not have a huge amount of experience in Go, and most of what I’ve done has been scratching my own itch.
This tool was written for Go 1.5.2 and used Godeps. I ripped out all the Godeps stuff and bumped up the version to 1.6 and that was fine. What was really frustrating was the absolute imports — every time it referenced itself via “github.com/rancher/external-dns/something” I had to change that to my fork. I’m not completely sure that that import style is necessary, but my primary goal was to add functionality, not refactor. 
I did do a little refactoring because I couldn’t quite figure out how to make something work after I broke it. I made the provider settable via an environment variable which helped me move forward. It might have been related to the change in Go version.
If your goal is for personal use, feel free to fork mine at github.com/mathuin/external-dns and change all the references from mathuin to your Github name and you should be good to go!
I think there’s still a bug in my implementation with respect to deleting records, I can’t recall. I should look at that sometime!