Upgrade to support Dokku 0.7.x

[pascalw]

dokku release is no longer a public command and the dokku tags:deploy functionality can be neatly used for this instead.

[pascalw]

Hi @dclucas @mavdi are you still maintaining this repo?

[chrisnicola]

Honestly this functionality should really be rolled into dokku itself. Being able to log into a registry other than docker hub is insanely useful.

[polettix]

@pascalw @josegonzalez would it be OK for you if the links in the plugins doc are updated to point towards pascalw's fork instead?

I can file a PR if you agree.

[pascalw]

@polettix I don't mind per se, but I'm not actively maintaining my fork either (I'm not even using it anymore) so I don't think that's much of an improvement.

[polettix]

Well, it seems the best we have around and you also seem to answer, so at least we shouldn't end up in this situation. Otherwise I don't mind taking over/forking your fork and manage PRs in the future.

[pascalw]

Ok, no problem. I dont mind responding to the occasional comment and besides I don't expect the plugin needing much changes anyway.

[mavdi]

This repo is no longer being maintained. I don't personally have write access to it to merge PRs but I can ask people that could do or ask to transfer ownership to someone else.

[josegonzalez]

If possible, would be great to transfer to dokku-community. I can coordinate that change with whomever has admin rights on this repo (they need to temporarily have dokku-community owner rights).

[mavdi]

OK let me reach out and try to find the person in charge of this.

[swrobel]

Did this go anywhere, or is there still no maintained fork of this?

[josegonzalez]

There is an official plugin maintained here: https://github.com/dokku/dokku-registry