Unfortunately with Ruby 2.2 and ActiveSupport 3.2.19 (used in latest 1.5.2 Gem release) or 3.2.21 (used on Github master branch) the following warning is shown with Ruby 2.2:

/.rbenv/versions/2.2.0/lib/ruby/gems/2.2.0/gems/activesupport-3.2.21/lib/active_support/values/time_zone.rb:270: warning: circular argument reference - now

It would be great to get this warning removed by upgrading to a later version of ActiveSupport if possible.