在Rails 3中，專門用于在資產(chǎn)管道中生成資產(chǎn)的gem被正確放置在assetsGemfile組中：...# Gems used only for assets and not required# in production environments by default.group :assets do  gem 'sass-rails'  gem 'coffee-rails'  gem 'uglifier'  # See https://github.com/sstephenson/execjs#readme for more supported runtimes  # gem 'therubyracer', :platforms => :rubyend現(xiàn)在，根據(jù)（仍在進行中的）升級文檔：Rails 4.0從Gemfile中刪除了資產(chǎn)組。升級時，您需要從Gemfile中刪除該行。當(dāng)然，使用RC1進行新項目會產(chǎn)生一個Gemfile，其中默認(rèn)包含任何組之外的資產(chǎn)相關(guān)的gem：source 'https://rubygems.org'# Bundle edge Rails instead: gem 'rails', github: 'rails/rails'gem 'rails', '4.0.0.rc1'# Use sqlite3 as the database for Active Recordgem 'sqlite3'# Use SCSS for stylesheetsgem 'sass-rails', '~> 4.0.0.rc1'# Use Uglifier as compressor for JavaScript assetsgem 'uglifier', '>= 1.3.0'# Use CoffeeScript for .js.coffee assets and viewsgem 'coffee-rails', '~> 4.0.0'# See https://github.com/sstephenson/execjs#readme for more supported runtimes# gem 'therubyracer', platforms: :ruby...這是否意味著這些寶石現(xiàn)在將默認(rèn)捆綁在生產(chǎn)版本中？如果是這樣，為什么會改變主意？Rails 4是否正在朝著生產(chǎn)中動態(tài)生成資產(chǎn)的方向邁進？