Upgrade ruby rails

Trello: https://trello.com/c/CJU4lEXu

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Upgrading Ruby to fix vulnerability described here: https://www.ruby-lang.org/en/news/2013/11/22/heap-overflow-in-floating-point-parsing-cve-2013-4164/

Rails 3.2.15 is expected to be the latest release for Rails 3.

OS X 10.9 Mavericks had some issues with older versions of libv8 and pg, so these gems have been updated.