Add installing Xcode tools from command line

Thanks to @leebailey88 for the tip

Author: nicolashery

README.md

@@ -79,6 +79,8 @@ Now, Xcode weights something like 2GB, and you don't need it unless you're devel
 
 Once you reach the downloads page, search for "command line tools", and download the latest **Command Line Tools (OS X Mountain Lion) for Xcode**. Open the **.dmg** file once it's done downloading, and double-click on the **.mpkg** installer to launch the installation. When it's done, you can unmount the disk in Finder.
 
+**Note**: If you are running **OS X 10.9 Mavericks**, then you can install the Xcode Command Line Tools directly from the command line with `$ xcode-select --install`, and you don't have to go through the download page and the questionnaire.
+
 Finally, we can install Hombrew! In the terminal paste the following line (without the `$`), hit **Enter**, and follow the steps on the screen:
 
     $ ruby -e "$(curl -fsSL https://raw.github.com/mxcl/homebrew/go/install)"