[lengarvey]

I wrote a slightly different article: http://bottledup.net/2013/01/10/bundler-and-gemfile/

It focuses on Bundler and your Gemfiles so that people understand not only how to update rails, but their other gems too. Personally I don't like rvm gemsets for bundler controlled apps (like rails) and think that rvm, bundler, rubygems and so on only serve to confuse the same part-time and hobby developers.