我试图从 rails 4.2 升级到 5。我的 ruby 版本和 rails 版本现在都升级了，我尝试完成我认为是大多数升级步骤的步骤。当我运行 rails server 时，服务器会启动，但是当我访问 localhost:3000 时，浏览器会抛出错误。
奇怪的是终端/日志根本没有抛出任何错误。我在日志中看到了这一点：
iMac:appDirectory name$ rails server
DEPRECATION WARNING: alias_method_chain is deprecated. Please, use Module#prepend instead. From module, you can access the original method using super. (called from block in <top (required)> at /Users//.rvm/gems/ruby-2.4.0@global/gems/gretel-3.0.8/lib/gretel/deprecated/default_style_key.rb:10)
DEPRECATION WARNING: alias_method_chain is deprecated. Please, use Module#prepend instead. From module, you can access the original method using super. (called from block in <top (required)> at /Users//.rvm/gems/ruby-2.4.0@global/gems/gretel-3.0.8/lib/gretel/deprecated/show_root_alone.rb:11)
DEPRECATION WARNING: alias_method_chain is deprecated. Please, use Module#prepend instead. From module, you can access the original method using super. (called from block in <top (required)> at /Users//.rvm/gems/ruby-2.4.0@global/gems/gretel-3.0.8/lib/gretel/deprecated/yield_links.rb:19)
DEPRECATION WARNING: Accessing mime types via constants is deprecated. Please change `Mime::HTML` to `Mime[:html]`. (called from <class:Request> at /Users//.rvm/gems/ruby-2.4.0@global/gems/web-console-2.2.1/lib/web_console/request.rb:7)
DEPRECATION WARNING: Accessing mime types via constants is deprecated. Please change `Mime::TEXT` to `Mime[:text]`. (called from <class:Request> at /Users//.rvm/gems/ruby-2.4.0@global/gems/web-console-2.2.1/lib/web_console/request.rb:7)
DEPRECATION WARNING: Accessing mime types via constants is deprecated. Please change `Mime::URL_ENCODED_FORM` to `Mime[:url_encoded_form]`. (called from <class:Request> at /Users//.rvm/gems/ruby-2.4.0@global/gems/web-console-2.2.1/lib/web_console/request.rb:7)
=> Booting WEBrick
=> Rails 5.0.1 application starting in development on http://localhost:3000
=> Run `rails server -h` for more startup options
[2017-02-26 00:51:50] INFO WEBrick 1.3.1
[2017-02-26 00:51:50] INFO ruby 2.4.0 (2016-12-24) [x86_64-darwin15]
[2017-02-26 00:51:50] INFO WEBrick::HTTPServer#start: pid=xxxxx port=3000
Started GET "/" for ::1 at 2017-02-26 00:51:57 -0600
我相信这可能只是我忘记的一些愚蠢的事情（并且根本与 rails 5 升级无关）但我有点难过，因为即使 localhost:3000 抛出我也看不到任何错误消息：
We're sorry, but something went wrong.
If you are the application owner check the logs for more information.
感谢您的帮助...