Rails 3.1 Beta 1 on Heroku Working Config

Gemfile

# source 'http://rubygems.org'
source :gemcutter

gem 'rails', '3.1.0.beta1'

# Asset template engines
gem 'json'
gem 'sass'
gem 'coffee-script'
gem 'uglifier'
gem 'jquery-rails'

group :production do
  gem 'therubyracer-heroku', '0.8.1.pre3'
  gem 'pg', :require => 'pg'
end

group :development do
  gem "therubyracer", :require => 'v8'
end

Production.rb

# Enable Rails's static asset server for heroku

config.serve_static_assets = true