The plugin executes scripts in any one of several languages (e.g. Groovy or BeanShell) as part of your build.
Free, full length book on Selenium WebDriver
Free, Selenium 3.0 compatible, and at over 420 pages this book is a hands-on guide to dozens of specific ways you can use to get the most of WebDriver in your test automation development.
This book will help you learn the fundamentals of the WebDriver API such as locating and interacting with web pages, through advanced topics such as Page Objects and mobile testing, and finally teach you how to build up your own web application testing framework.