使用$ rails服务器时，在终端中“无法加载此类文件 - 设计（LoadError）”

Question

我是rails的新手，在tutorial我正在处理devise时遇到问题。

当尝试测试应用程序（之前工作正常）并启动$ rails s时，我得到以下堆栈跟踪：

Patricks-MacBook-Air:rails-prelaunch-signup patrickvihtelic$ rails s
/Users/patrickvihtelic/code/rails-prelaunch-signup/config/application.rb:13:in `require': cannot load such file -- devise (LoadError)
    from /Users/patrickvihtelic/code/rails-prelaunch-signup/config/application.rb:13:in `<top (required)>'
    from /Users/patrickvihtelic/.rvm/gems/ruby-1.9.3-p194@rails326/gems/railties-3.2.8/lib/rails/commands.rb:53:in `require'
    from /Users/patrickvihtelic/.rvm/gems/ruby-1.9.3-p194@rails326/gems/railties-3.2.8/lib/rails/commands.rb:53:in `block in <top (required)>'
    from /Users/patrickvihtelic/.rvm/gems/ruby-1.9.3-p194@rails326/gems/railties-3.2.8/lib/rails/commands.rb:50:in `tap'
    from /Users/patrickvihtelic/.rvm/gems/ruby-1.9.3-p194@rails326/gems/railties-3.2.8/lib/rails/commands.rb:50:in `<top (required)>'
    from script/rails:6:in `require'
    from script/rails:6:in `<main>'

任何提示或建议都会非常感激 - 谢谢！