ruby-on-rails – Rails 4.2 web-console问题

在Rails 4.2的发行说明中,它提到：“使用Rails 4.2生成的新应用程序现在默认带有Web控制台gem.”

自从我升级到4.2后,我认为这意味着我仍然需要在我的Gemfile中指定它.没有将它添加到我的Gemfile中,rails只给我“未定义的局部变量或方法`console’”,所以我认为是这样的.

一旦我添加了gem’web-console’,’?> 2.0’到Gemfile,并运行rails服务器,我现在得到：

/home/kevin/.rvm/gems/ruby-2.1.5/gems/binding_of_caller-0.7.3.pre1/lib/binding_of_caller/mri2.rb:21:in `callers': uninitialized constant RubyVM::DebugInspector (NameError)
  from /home/kevin/.rvm/gems/ruby-2.1.5/gems/better_errors-2.0.0/lib/better_errors/exception_extension.rb:7:in `set_backtrace'
  from /home/kevin/.rvm/gems/ruby-2.1.5@global/gems/bundler-1.7.6/lib/bundler/runtime.rb:76:in `require'
  from /home/kevin/.rvm/gems/ruby-2.1.5@global/gems/bundler-1.7.6/lib/bundler/runtime.rb:76:in `block (2 levels) in require'
  from /home/kevin/.rvm/gems/ruby-2.1.5@global/gems/bundler-1.7.6/lib/bundler/runtime.rb:72:in `each'
  from /home/kevin/.rvm/gems/ruby-2.1.5@global/gems/bundler-1.7.6/lib/bundler/runtime.rb:72:in `block in require'
  from /home/kevin/.rvm/gems/ruby-2.1.5@global/gems/bundler-1.7.6/lib/bundler/runtime.rb:61:in `each'
  from /home/kevin/.rvm/gems/ruby-2.1.5@global/gems/bundler-1.7.6/lib/bundler/runtime.rb:61:in `require'
  from /home/kevin/.rvm/gems/ruby-2.1.5@global/gems/bundler-1.7.6/lib/bundler.rb:133:in `require'
  from /home/kevin/workspace/applications/ems-heroes/config/application.rb:6:in `<top (required)>'
  from /home/kevin/.rvm/gems/ruby-2.1.5/gems/railties-4.2.0/lib/rails/commands/commands_tasks.rb:78:in `require'
  from /home/kevin/.rvm/gems/ruby-2.1.5/gems/railties-4.2.0/lib/rails/commands/commands_tasks.rb:78:in `block in server'
  from /home/kevin/.rvm/gems/ruby-2.1.5/gems/railties-4.2.0/lib/rails/commands/commands_tasks.rb:75:in `tap'
  from /home/kevin/.rvm/gems/ruby-2.1.5/gems/railties-4.2.0/lib/rails/commands/commands_tasks.rb:75:in `server'
  from /home/kevin/.rvm/gems/ruby-2.1.5/gems/railties-4.2.0/lib/rails/commands/commands_tasks.rb:39:in `run_command!'
  from /home/kevin/.rvm/gems/ruby-2.1.5/gems/railties-4.2.0/lib/rails/commands.rb:17:in `<top (required)>'
  from bin/rails:4:in `require'
  from bin/rails:4:in `<main>'

我用Google搜索并没有找到太多东西.任何意见是极大的赞赏.

谢谢！