Have you added:
config.assets.initialize_on_precompile = false
to config / application.rb? This was the last step I took to fix my problems with Heroku.
You should also leave gem 'bootstrap-sass', '~> 2.0.3'in your block group assets do, despite what I read on the Internet.
gem, , Heroku:
source 'https://rubygems.org'
group :development, :test do
gem 'rspec-rails', '2.9.0'
gem 'guard-rspec', '0.5.5'
end
group :test do
gem 'capybara', '1.1.2'
end
group :assets do
gem 'sass-rails', '~> 3.2.3'
gem 'coffee-rails', '~> 3.2.1'
gem 'uglifier', '>= 1.0.3'
gem 'bootstrap-sass', '~> 2.0.3'
end
gem 'rails', '3.2.2'
gem 'pg', '0.13.2'
gem 'jquery-rails', '2.0.2'
gem 'simple_form', '2.0.1'