s表明你确实没有使用Ruby 2.0来安装你的宝石，而是系统提供的1.8.7。这可能是由于使用 sudo 。

The stack traces indicate that you are indeed not using Ruby 2.0 for installing your gems, but the system-provided 1.8.7. This is probably caused by your use of sudo.

如果您使用RVM安装了Ruby 2.0.0，你必须使用 rvmsudo 来代替它，它可以确保rvm对 $ PATH 的更改加载特定的红宝石版本将可用于以root身份运行的程序。默认情况下， sudo 会清理 $ PATH 并且会避免更改。

If you have installed your Ruby 2.0.0 using RVM, you have to use rvmsudo instead which will make sure that the changes rvm does to the $PATH to load a specific ruby version will be available to the program run as root. By default, sudocleans up the $PATH and will revent the changes.