了解Rails 5升级对gems的版本兼容性

Question

我正在尝试使用以下命令更新当前4.1.4的Rails应用程序：

gem 'rails', '>= 5.0.0.rc2', '< 5.1'

将其添加到我的gemfile中并运行bundle update rails

我收到以下消息（以及其他消息）：

Bundler could not find compatible versions for gem "actionpack":
  In Gemfile:
     activerecord-session_store (~> 1.1.1) was resolved to 1.1.1, which depends on
  actionpack (>= 4.0)

jquery-fileupload-rails (~> 0.4.7) was resolved to 0.4.7, which depends on
  actionpack (>= 3.1)

rails (< 5.1, >= 5.0.0.rc2) was resolved to 5.0.0.rc2, which depends on
  actionpack (= 5.0.0.rc2)

rspec-rails (~> 3.5.2) was resolved to 3.5.2, which depends on
  actionpack (>= 3.0)

是不是说rspec-rails将升级限制为3.0？是否因为说一切都在Rails 3.0或更高版本而兼容？我试图找出它告诉我的版本与该gem的升级冲突。

请让我知道。

谢谢！