Update Ruby version to 2.1.1 / deal with gem dependencies

We've had issues while trying to upgrade [Passenger](https://www.phusionpassenger.com/) on the new reservations server (vm-rordevweb-04). Via Michael Dunlap / ITS:
> No logs that appear to be worth anything.  It looks to me like there’s a ruby preloader that tries to run for each application.  If the app can be run, then a Passenger AppPreloader process runs which kicks off Passenger RackApp processes to handle http requests. 
> 
> Since the f5 keeps hitting the reservations apps for a health check, that initial preloader keeps trying to run.  System load drives way up.  The configurations tested so far are:
> 
> ruby 1.9.3 (binary distribution) + passenger 3 - works, but is a bit slow
> ruby 1.9.3 (from source via rvm) + passenger 4 - some apps work, shifts/reservations fail to load
> ruby 2.1.1 (from source via rvm) + passenger 4 - most apps work, except reservations which complain about debugger 1.6.2 not being compatible with ruby 2.1.1.
> 
> Debugger 1.6.6 supports ruby 2.1.1, for what it’s worth, but your Gemfile.lock demands version 1.6.2.

@caseywatts' reply:
> I think it sounds like we may want to update the Ruby version on Dev and then do some testing on Dev this week.
> 
> We can work through removing the dependency on debugger 1.6.2. It's a nested dependency so we may not be able to update it directly but we can switch to pry-byebug and that shouldn't affect us much.
> http://www.justinweiss.com/blog/2014/01/21/should-i-upgrade-to-ruby-2-dot-1/

We should try to figure out our dependency issues and get a branch running on Ruby 2.1.1, this will hopefully both improve performance and help with future upgrades.