Problems with sprockets when deploying Rails 3.1.rc4

I'm sure that I am just overlooking something simple here but this has been driving me crazy all night! When trying to deploy a Rails 3.1.rc4 application to the Cedar stack on Heroku (I did this successfully a month ago with a similar Gemfile) I am receiving this error:

Could not find sprockets-2.0.0.beta.10 in any of th开发者_StackOverflow社区e sources

My Gemfile looks like this:

source 'http://rubygems.org'

# Core
gem 'rails', '3.1.0.rc4'

# Asset template engines
gem 'sass-rails', "~> 3.1.0.rc"
gem 'coffee-script'
gem 'uglifier'

# Misc
gem 'devise'
gem 'jquery-rails'
gem 'omniauth'
gem 'fb_graph'
gem 'compass', git: 'https://github.com/chriseppstein/compass.git', branch: 'rails31'
gem 'haml'
gem 'cancan'
gem 'kaminari'
gem 'friendly_id', '~> 3.3.0', git: 'https://github.com/norman/friendly_id.git'
gem 'recaptcha', :require => 'recaptcha/rails'
gem 'aws-ses', '~> 0.4.3', :require => 'aws/ses'

# Local Environment
group :test do
  # Pretty printed test output
  gem 'turn', :require => false
    gem 'sqlite3'
end

# Heroku Environment
group :production do
    gem 'pg'
    gem 'execjs'
    gem 'therubyracer'
end

After searching around and finding this article on Google Groups, I determined that this must be fixable by adding this line

gem 'sprockets', '2.0.0.beta10'

to my Gemfile and then running

bundle update sprockets

This failed with

Could not find gem 'sprockets (= 2.0.0.beta10, runtime)' in any of the gem sources listed in your Gemfile.

and at this point I don't know what to do or how to handle this. Is it possible that I need to upgrade to Rails 3.1.rc5 and if so how may I do that without starting over from scratch?

Thank you for any help that you can provide!

-Robert

Just bump your rails version up to rc5

gem 'rails', '3.1.0rc5'

then:

bundle update