当我通过 cpanel 启动我的应用程序时，我得到了这个日志。
** 在 0.0.0.0:12001 开始 Mongrel 监听
** 使用生产环境启动 Rails...
/home/pixelcor/ruby/gems/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:158:in `require': 没有要加载的文件 -- readline (MissingSourceFile)
来自/home/pixelcor/ruby/gems/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:158:in `require'
来自/home/pixelcor/ruby/gems/gems/rush-0.6.8/lib/rush/shell.rb:1
来自/home/pixelcor/ruby/gems/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:158:in `require'
来自/home/pixelcor/ruby/gems/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:158:in `require'
来自/home/pixelcor/ruby/gems/gems/rush-0.6.8/lib/rush/embeddable_shell.rb:1
来自/home/pixelcor/ruby/gems/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:158:in `require'
来自/home/pixelcor/ruby/gems/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:158:in `require'
来自/home/pixelcor/ruby/gems/gems/rush-0.6.8/lib/rush.rb:87
来自 /home/pixelcor/ruby/gems/gems/bundler-1.3.5/lib/bundler/runtime.rb:72:in `require'
来自 /home/pixelcor/ruby/gems/gems/bundler-1.3.5/lib/bundler/runtime.rb:72:in `require'
来自 /home/pixelcor/ruby/gems/gems/bundler-1.3.5/lib/bundler/runtime.rb:70:in `each'
来自 /home/pixelcor/ruby/gems/gems/bundler-1.3.5/lib/bundler/runtime.rb:70:in `require'
来自 /home/pixelcor/ruby/gems/gems/bundler-1.3.5/lib/bundler/runtime.rb:59:in `each'
来自 /home/pixelcor/ruby/gems/gems/bundler-1.3.5/lib/bundler/runtime.rb:59:in `require'
来自 /home/pixelcor/ruby/gems/gems/bundler-1.3.5/lib/bundler.rb:132:in `require'
来自 /home/pixelcor/rails_apps/demo/config/boot.rb:117:in `load_gems'
来自 /home/pixelcor/ruby/gems/gems/rails-2.3.5/lib/initializer.rb:164:in `process'
来自 /home/pixelcor/ruby/gems/gems/rails-2.3.5/lib/initializer.rb:113:in `send'
来自 /home/pixelcor/ruby/gems/gems/rails-2.3.5/lib/initializer.rb:113:in `run'
来自/home/pixelcor/rails_apps/demo/config/environment.rb:17
来自 /usr/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require'
来自 /usr/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `require'
来自 /usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/bin/../lib/mongrel/rails.rb:147:in `rails'
来自 /usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/bin/mongrel_rails:113:in `cloaker_'
来自 /usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/bin/../lib/mongrel/configurator.rb:149:in `call'
来自 /usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/bin/../lib/mongrel/configurator.rb:149:in `listener'
来自 /usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/bin/mongrel_rails:99:in `cloaker_'
来自 /usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/bin/../lib/mongrel/configurator.rb:50:in `call'
来自 /usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/bin/../lib/mongrel/configurator.rb:50:in `initialize'
来自 /usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/bin/mongrel_rails:84:in `new'
来自 /usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/bin/mongrel_rails:84:in `run'
来自 /usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/bin/../lib/mongrel/command.rb:212:in `run'
来自 /usr/lib/ruby/gems/1.8/gems/mongrel-1.1.5/bin/mongrel_rails:281
来自 /usr/bin/mongrel_rails:23:in `load'
来自 /usr/bin/mongrel_rails:23
任何人都可以帮助我克服这个错误。