config.assets.compile = true
back
production.rb
attr_accessibleを設定
back
gem 'rails_12factor', group: :production
rake rails:update:bin
gem 'rails_log_stdout',           github: 'heroku/rails_log_stdout'
gem 'rails3_serve_static_assets', github: 'heroku/rails3_serve_static_assets'
http://railscasts.com/episodes/415-upgrading-to-rails-4