using compass in rails 3.1.3

group :assets do
  gem 'sass-rails',   '~> 3.1.5'
  gem 'coffee-rails', '~> 3.1.1'
  gem 'uglifier', '>= 1.0.3'
  gem 'compass', '>= 0.12.alpha'
end

config.assets.precompile << /(^[^_]|\/[^_])[^\/]*$/