Omni config

[chazzly]

Adds an option to skip the promote step within the omni command. Can be set in spork-config.yml with the directive:
omni_promote: false

default remains true.

This setting can be overridden with the --promote option on the command line.

[jonlives]

@chazzly I have somewhat mixed feelings about making the exact steps taken by Omni configurable, because it was designed to do a full "bump, upload, promote".

My concern is that the more options added to omni which enable / disable parts of it, the more confusing it will be to use - effectively, the steps carried out by Omni could vary drastically depending on what config file you happen to be using.

With that said, I'm not saying I won't accept this PR, I just need to give the matter some thought. As a heads up though, it's probably not going to be out in the next release (which I hope to have done by the end of next week).

Could you give any more info on your specific use case for this feature?

[chazzly]

Well, to be honest, we're still on the rapid ascent part of the learning curve so our structure & processes are evolving fairly quickly. We have a small test chef instance where we do our cookbook development and testing and such. We were working out of one git repo and had overlapping chef environment names, so we couldn't effectively use the promote option without risking unintended changes to the production chef_enviornments. I was looking for a way to keep the bump, foodcritc & rubocop checks (my other pull request) and the version freeze functions, without the promote, while still keeping things simple for my team.

Omni would be perfect if I could only turn off the promote step.

That said, since I wrote this, two weeks ago, we have split out our git repo into separate branches for production and test and we've eliminated the overlapping environment names. With those changes, we can effectively and safely use the local environment json files and take advantage of the spork promote function.

I went ahead and did the pull request thinking that someone else may find it useful as we did, though briefly.

[jonlives]

@chazzly thanks for the detailed info! I'm going to have a think through what's best to do here - either way though, thanks for the contribution!