Constant autoloading works fine for gems loaded using config.gem, but fails for
gems loaded manually using "gem 'name'; require 'name'". The problem appears to be
that ActiveSupport::Dependencies.load_paths doesn't get updated when Gem.activate
adds stuff to $LOAD_PATH.
Most annoyingly, this means that gem plugins can manifest an issue where they work
correctly from vendor/plugins but fail running from a gem.
See #1524 (http://rails.lighthouseapp.com/projects/8994-ruby-on-rails/tickets/1524) for more details.
If this behavior is acceptable, it should be documented. Alternatively, it should be fixed
(sample code in the ticket). I'd be glad to put together a patch, but how would one write a test for this?