`在块中抢救（2级）需要’：尝试加载gem’sass-rails’时出错。 （捆扎机:: GemRequireError）

我完成了在我的ubuntu系统（16.04.2 LTS）上安装rails 5，当我尝试运行rails server命令时，我遇到了这个错误。

`rescue in block (2 levels) in require': There was an error while trying to load the gem 'sass-rails'. (Bundler::GemRequireError) 

gem加载错误是：未初始化的常量Sass :: Script你的意思是？ ScriptError

当我写捆绑更新时，提示显示此消息：

 The dependency tzinfo-data (>= 0) will be unused by any of the platforms Bundler is installing for. Bundler is installing for ruby but the dependency is only for x86-mingw32, x86-mswin32, x64-mingw32, java. To add those platforms to the bundle, run `bundle lock --add-platform x86-mingw32 x86-mswin32 x64-mingw32 java`. 

然后它更新…并显示~≳使用sass-rails 5.0.6

请帮帮我吧，问候！