Remove Gemfile.lock
Update Rails to 3.2.13.

This addresses [CVE-2013-1855] XSS vulnerability in sanitize_css in
Action Pack. See
https://groups.google.com/forum/?fromgroups=#!topic/rubyonrails-security/4_QHo4BqnN8
for the announcement.
Merge pull request #21 from BanzaiMan/master

Remove Gemfile.lock, and update to Rails 3.2.13.