Rails 4.0.0.beta1でcapistrano

とりあえず、gemが対応されるまでこれで凌ごうかと。

1. Gemfile
gem 'capistrano', group: :development
2. cap deployでエラー... orz
cp: cannot stat `/var/www/sandbox/shared/assets/manifest.yml': No such file or directory
3. 原因

Rails 4 support · Issue #362 · capistrano/capistrano · GitHub

Rails 4 store manifest in JSON file like manifest-effbd5715fcc7c1600baa48c1bc283ee.json, not in manifest.yml. So right now we can’t deploy Rails 4 application.
4. config/deploy.rb に以下を追加
namespace :deploy do
  namespace :assets do
    task :precompile, :roles => assets_role, :except => { :no_release => true } do
      run <<-CMD.compact
        cd -- #{latest_release.shellescape} &&
        #{rake} RAILS_ENV=#{rails_env.to_s.shellescape} #{asset_env} assets:precompile
      CMD
    end
  end
end

Source: Rails 4 support · Issue #362 · capistrano/capistrano · GitHub