我刚刚开始研究Rails，无法让服务器运行。我正在运行ruby 2.3.0和rails
4.2.5，并且在我有一个新的rail项目之后，我尝试运行bin/rails server但出现以下错误：

Warning: Running `gem pristine --all` to regenerate your installed gemspecs (and deleting then reinstalling your bundle if you use bundle --path) will improve the startup performance of Spring.
/Users/John/.rvm/gems/ruby-head/gems/json-1.8.3/lib/json/ext.rb:13:in `require': incompatible library version - /Users/John/.rvm/gems/ruby-head/gems/json-1.8.3/lib/json/ext/parser.bundle (fatal)
    from /Users/John/.rvm/gems/ruby-head/gems/json-1.8.3/lib/json/ext.rb:13:in `<module:Ext>'
    from /Users/John/.rvm/gems/ruby-head/gems/json-1.8.3/lib/json/ext.rb:12:in `<module:JSON>'
    from /Users/John/.rvm/gems/ruby-head/gems/json-1.8.3/lib/json/ext.rb:9:in `<top (required)>'
    from /Users/John/.rvm/gems/ruby-head/gems/json-1.8.3/lib/json.rb:58:in `require'
    from /Users/John/.rvm/gems/ruby-head/gems/json-1.8.3/lib/json.rb:58:in `<module:JSON>'
    from /Users/John/.rvm/gems/ruby-head/gems/json-1.8.3/lib/json.rb:54:in `<top (required)>'
    from /Users/John/.rvm/gems/ruby-head/gems/activesupport-4.2.5/lib/active_support/core_ext/object/json.rb:2:in `require'
    from /Users/John/.rvm/gems/ruby-head/gems/activesupport-4.2.5/lib/active_support/core_ext/object/json.rb:2:in `<top (required)>'
    from /Users/John/.rvm/gems/ruby-head/gems/activesupport-4.2.5/lib/active_support/core_ext/object.rb:12:in `require'
    from /Users/John/.rvm/gems/ruby-head/gems/activesupport-4.2.5/lib/active_support/core_ext/object.rb:12:in `<top (required)>'
    from /Users/John/.rvm/gems/ruby-head/gems/railties-4.2.5/lib/rails/configuration.rb:2:in `require'
    from /Users/John/.rvm/gems/ruby-head/gems/railties-4.2.5/lib/rails/configuration.rb:2:in `<top (required)>'
    from /Users/John/.rvm/gems/ruby-head/gems/railties-4.2.5/lib/rails/railtie.rb:2:in `require'
    from /Users/John/.rvm/gems/ruby-head/gems/railties-4.2.5/lib/rails/railtie.rb:2:in `<top (required)>'
    from /Users/John/.rvm/gems/ruby-head/gems/railties-4.2.5/lib/rails/engine.rb:1:in `require'
    from /Users/John/.rvm/gems/ruby-head/gems/railties-4.2.5/lib/rails/engine.rb:1:in `<top (required)>'
    from /Users/John/.rvm/gems/ruby-head/gems/railties-4.2.5/lib/rails/application.rb:7:in `require'
    from /Users/John/.rvm/gems/ruby-head/gems/railties-4.2.5/lib/rails/application.rb:7:in `<top (required)>'
    from /Users/John/.rvm/gems/ruby-head/gems/railties-4.2.5/lib/rails.rb:11:in `require'
    from /Users/John/.rvm/gems/ruby-head/gems/railties-4.2.5/lib/rails.rb:11:in `<top (required)>'
    from /Users/John/.rvm/gems/ruby-head/gems/railties-4.2.5/lib/rails/commands/server.rb:4:in `require'
    from /Users/John/.rvm/gems/ruby-head/gems/railties-4.2.5/lib/rails/commands/server.rb:4:in `<top (required)>'
    from /Users/John/.rvm/gems/ruby-head/gems/railties-4.2.5/lib/rails/commands/commands_tasks.rb:123:in `require'
    from /Users/John/.rvm/gems/ruby-head/gems/railties-4.2.5/lib/rails/commands/commands_tasks.rb:123:in `require_command!'
    from /Users/John/.rvm/gems/ruby-head/gems/railties-4.2.5/lib/rails/commands/commands_tasks.rb:73:in `server'
    from /Users/John/.rvm/gems/ruby-head/gems/railties-4.2.5/lib/rails/commands/commands_tasks.rb:39:in `run_command!'
    from /Users/John/.rvm/gems/ruby-head/gems/railties-4.2.5/lib/rails/commands.rb:17:in `<top (required)>'
    from /Users/John/Developer/Rails/blog/bin/rails:9:in `require'
    from /Users/John/Developer/Rails/blog/bin/rails:9:in `<top (required)>'
    from /Users/John/.rvm/gems/ruby-head/gems/spring-1.6.1/lib/spring/client/rails.rb:28:in `load'
    from /Users/John/.rvm/gems/ruby-head/gems/spring-1.6.1/lib/spring/client/rails.rb:28:in `call'
    from /Users/John/.rvm/gems/ruby-head/gems/spring-1.6.1/lib/spring/client/command.rb:7:in `call'
    from /Users/John/.rvm/gems/ruby-head/gems/spring-1.6.1/lib/spring/client.rb:28:in `run'
    from /Users/John/.rvm/gems/ruby-head/gems/spring-1.6.1/bin/spring:51:in `<top (required)>'
    from /Users/John/.rvm/gems/ruby-head/gems/spring-1.6.1/lib/spring/binstub.rb:11:in `load'
    from /Users/John/.rvm/gems/ruby-head/gems/spring-1.6.1/lib/spring/binstub.rb:11:in `<top (required)>'
    from /Users/John/.rvm/rubies/ruby-head/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:54:in `require'
    from /Users/John/.rvm/rubies/ruby-head/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:54:in `require'
    from /Users/John/Developer/Rails/blog/bin/spring:13:in `<top (required)>'
    from bin/rails:3:in `load'
    from bin/rails:3:in `<main>'

宝石清单说我有json (1.8.3, 1.8.2)。我也尝试过重新安装rails并通过rvm更新我的ruby版本。知道有什么问题吗？我尝试过在网上四处看看，但是有点卡住了，尤其是因为我以前从未使用过滑轨，而只是使用了一点红宝石。