In Chapter 4 and throughout the remainder of the book, I show that you have to provide the path to a plugin in order to add it to your Cordova project. With Cordova 3.1, the development team finished implementing the Cordova Plugin Repository, so now you can add Cordova plugins to your project using the paths I showed in the book or by specifying the ID for the Cordova plugin.
So, where the book shows adding the Camera plugin using the following:
cordova plugin add https://git-wip-us.apache.org/repos/asf/cordova-plugin-camera.git
You could also add the plugin using the following:
cordova plugin add org.apache.cordova.camera
The Cordova CLI will connect to the repository and locate the latest version of the plugin for you automatically.