您可能需要安装Xcode控制台工具，而这至少是我遇到的问题.

You probably need to install the Xcode console tools, atleast that was the problem I had.

您可以通过运行以下操作来实现:

you can do this by running:

xcode-select --install

有关更多信息，请参见此链接

See this link for more information

在Mavericks上安装Rails