We pushed a build to RubyGems.org[1], so you should be able drop the github option now:

    gem 'rails', '4.1.0.beta1'

We upgraded a few apps in our local Ruby meetup group lately[2], and it's worth mentioning that you might need to upgrade the following gems too:

    gem 'rspec', '~> 3.0.0.beta1'
    gem 'rspec-rails', '~> 3.0.0.beta1'
    gem 'capybara', '~> 2.2.0'
    gem 'jquery-rails', github: 'takkanm/jquery-rails', branch:' fix_action_view_require'
    (I'm not 100% sure about the last one, might have been fixed since I last checked)

I'll try to write this up in another blog post tomorrow.

[1]: http://rubygems.org/gems/rails/versions/4.1.0.beta1

[2]: http://www.meetup.com/vancouver-ruby/messages/61805312/

Edit: minor formatting fixes