Benchmark graph parsing
Upgrade to Rails 3.2.12 to get security patches

There have been some recent Rails security patches that are critical.

Upgrade to the most recent version of Rails.  Use "bundle update", which
generates a new Gemfile.lock from scratch, so lots of other packages
have gotten upgraded as well, for better or worse.
Extract the Rails secret_token to an environment variable

This repository is open-source, so we must not store production
secrets in the repository.

Extract the secret_token used for signing sessions to an environment
variable, and replace it with a newly generated token.