Auto-merge schema version conflicts

[chrisarcand]

As mentioned by @ryanmuller, would be nice to have a way to auto-merge schema versions on things like stage-up and deploys. Would likely be a plugin of some sort as it's Rails specific.

Then when someone attempts to merge master for a deploy and gets a conflict, they don't necessarily have to require the author of the PR to sync-branch and ping them again, wasting time, for something as trivial as a schema version conflict.