在日志中可以找到500错误页面但没有错误

Question

我的ruby应用程序已成功启动，但当我转到localhost：3000时，我看到此页面：

检查production.log文件，它只有一行：

# Logfile created on Tue Oct 28 10:47:41 -0500 2014luser@luser-VirtualBox:~/Repo/adm$ 

Mongrel.log表示应用已成功启动：

** Daemonized, any open files are closed.  Look at log/mongrel.pid and log/mongrel.log for info.
** Starting Mongrel listening at 127.0.0.1:3000
** Starting Rails with production environment...
/home/luser/.rvm/gems/ruby-1.8.7-head/gems/rails-2.3.5/lib/rails/gem_dependency.rb:119:Warning:    Gem::Dependency#version_requirements is deprecated and will be removed on or after August 2010.  Use #requirement
** Rails loaded.
** Loading any Rails specific GemPlugins
** Signals ready.  TERM => stop.  USR2 => restart.  INT => stop (no restart).
** Rails signals registered.  HUP => reload (without restart).  It might not work well.
** Mongrel 1.1.5 available at 127.0.0.1:3000
** Writing PID file to log/mongrel.pid

如何解决此问题？