Microsoft SQL support

[btrepp]

Would it be desired to add in sqlserver as a backend?. Kine seems really handy for situations in which running etcd is tricky.

I think it's not too disamilar to existing SQL backends, so hopefully isn't too bad, but it's there any philosophical reasons against it?. Or just a no one has needed it yet?.

[warmchang]

Here is a PR #43 from @ibrokethecloud

[btrepp]

Fantastic. I will close this issue and keep an eye on the PR :)