Updating our 2+ year old fork to latest master of original

We use this fork of a gem for Performance Management, but we do so via the deploy branch.  This PR simply updates this fork's master branch which is independent.  The goal here is to catch up this gem to current and see if the functionality we added has been added to the gem.

The original intent with this fork (I believe) was to send a pull request.  I'm not certain that ever happened.

As an aside for anyone reading this, we manage tree structures through SQL (e.g. organizational_units) and there are a few techniques to doing so.  We appear to be using a hybrid of the adjacency and nested set techniques.  The nested set technique appears isolated to performance management.  From what I have researched, the adjacency technique is the slowest.  Why is that important to point out?  Because we have performance problems around our tree querying.  Going fully to nested set might be a step toward helping us mitigate our performance problem for employers like UoF.

But again, I'm not doing anything here but updating our fork's master branch.  I'm leaving our deploy branch (which is used) unchanged.