Jekyll buid使用grunt响应图像失败

嗨，这是我运行jekyll build时的终端输出

    Configuration file: /Users/makingthings/Dropbox/Sites/jekyll-uh/_config.yml
/usr/local/Cellar/ruby/2.2.2/lib/ruby/2.2.0/rubygems/core_ext/kernel_require.rb:54:in `require': cannot load such file -- jekyll-responsive_image (LoadError)
    from /usr/local/Cellar/ruby/2.2.2/lib/ruby/2.2.0/rubygems/core_ext/kernel_require.rb:54:in `require'
    from /usr/local/lib/ruby/gems/2.2.0/gems/jekyll-2.5.3/lib/jekyll/plugin_manager.rb:29:in `block in require_gems'
    from /usr/local/lib/ruby/gems/2.2.0/gems/jekyll-2.5.3/lib/jekyll/plugin_manager.rb:26:in `each'
    from /usr/local/lib/ruby/gems/2.2.0/gems/jekyll-2.5.3/lib/jekyll/plugin_manager.rb:26:in `require_gems'
    from /usr/local/lib/ruby/gems/2.2.0/gems/jekyll-2.5.3/lib/jekyll/plugin_manager.rb:19:in `conscientious_require'
    from /usr/local/lib/ruby/gems/2.2.0/gems/jekyll-2.5.3/lib/jekyll/site.rb:79:in `setup'
    from /usr/local/lib/ruby/gems/2.2.0/gems/jekyll-2.5.3/lib/jekyll/site.rb:41:in `initialize'
    from /usr/local/lib/ruby/gems/2.2.0/gems/jekyll-2.5.3/lib/jekyll/commands/build.rb:29:in `new'
    from /usr/local/lib/ruby/gems/2.2.0/gems/jekyll-2.5.3/lib/jekyll/commands/build.rb:29:in `process'
    from /usr/local/lib/ruby/gems/2.2.0/gems/jekyll-2.5.3/lib/jekyll/commands/build.rb:18:in `block (2 levels) in init_with_program'
    from /usr/local/lib/ruby/gems/2.2.0/gems/mercenary-0.3.5/lib/mercenary/command.rb:220:in `call'
    from /usr/local/lib/ruby/gems/2.2.0/gems/mercenary-0.3.5/lib/mercenary/command.rb:220:in `block in execute'
    from /usr/local/lib/ruby/gems/2.2.0/gems/mercenary-0.3.5/lib/mercenary/command.rb:220:in `each'
    from /usr/local/lib/ruby/gems/2.2.0/gems/mercenary-0.3.5/lib/mercenary/command.rb:220:in `execute'
    from /usr/local/lib/ruby/gems/2.2.0/gems/mercenary-0.3.5/lib/mercenary/program.rb:42:in `go'
    from /usr/local/lib/ruby/gems/2.2.0/gems/mercenary-0.3.5/lib/mercenary.rb:19:in `program'
    from /usr/local/lib/ruby/gems/2.2.0/gems/jekyll-2.5.3/bin/jekyll:20:in `<top (required)>'
    from /usr/local/bin/jekyll:23:in `load'
    from /usr/local/bin/jekyll:23:in `<main>'

配置文件：/Users/makingthings/Dropbox/Sites/jekyll-uh/_-config.yml
/usr/local/ceral/ruby/2.2.2/lib/ruby/2.2.0/rubygems/core\u ext/kernel\u require.rb:54:在“require”中：无法加载这样的文件--jekyll-responsive\u映像（LoadError）
from/usr/local/ceral/ruby/2.2.2/lib/ruby/2.2.0/rubygems/core\u ext/kernel\u require.rb:54:in'require'
from/usr/local/lib/ruby/gems/2.2.0/gems/jekyll-2.5.3/lib/jekyll/plugin\u manager.rb:29:in“block in require\u gems”
from/usr/local/lib/ruby/gems/2.2.0/gems/jekyll-2.5.3/lib/jekyll/plugin_manager.rb:26:in'each'
来自/usr/local/lib/ruby/gems/2.2.0/gems/jekyll-2.5.3/lib/jekyll/plugin\u manager.rb:26:in'require\u gems'
from/usr/local/lib/ruby/gems/2.2.0/gems/jekyll-2.5.3/lib/jekyll/plugin\u manager.rb:19:in'certificious\u require'
from/usr/local/lib/ruby/gems/2.2.0/gems/jekyll-2.5.3/lib/jekyll/site.rb:79:in'setup'
from/usr/local/lib/ruby/gems/2.2.0/gems/jekyll-2.5.3/lib/jekyll/site.rb:41:in'initialize'
from/usr/local/lib/ruby/gems/2.2.0/gems/jekyll-2.5.3/lib/jekyll/commands/build.rb:29:in'new'
from/usr/local/lib/ruby/gems/2.2.0/gems/jekyll-2.5.3/lib/jekyll/commands/build.rb:29:在“进程”中
from/usr/local/lib/ruby/gems/2.2.0/gems/jekyll-2.5.3/lib/jekyll/commands/build.rb:18:in`block（2层）in init_with_program'
from/usr/local/lib/ruby/gems/2.2.0/gems/雇佣军-0.3.5/lib/雇佣军/command.rb:220:in'call'
from/usr/local/lib/ruby/gems/2.2.0/gems/雇佣军-0.3.5/lib/雇佣军/command.rb:220:in'block in execute'
from/usr/local/lib/ruby/gems/2.2.0/gems/雇佣军-0.3.5/lib/雇佣军/command.rb:220:in'each'
from/usr/local/lib/ruby/gems/2.2.0/gems/雇佣军-0.3.5/lib/雇佣军/command.rb:220:in'execute'
from/usr/local/lib/ruby/gems/2.2.0/gems/雇佣军-0.3.5/lib/雇佣军/program.rb:42:in'go'
from/usr/local/lib/ruby/gems/2.2.0/gems/雇佣军-0.3.5/lib/雇佣军。rb:19:in“程序”
from/usr/local/lib/ruby/gems/2.2.0/gems/jekyll-2.5.3/bin/jekyll:20:in`'
from/usr/local/bin/jekyll:23:in'load'
from/usr/local/bin/jekyll:23:in`'

---

可能存在冲突的ruby环境？

对ruby不太熟悉，但我在使用config时得到了如下结果：

gems: [jekyll/responsive_image]