This is the standard introductory sample application for Grails. To get started with it, simply clone the repository and then from within your local copy run:
./gradlew run
on Unix-like systems, or
gradlew run
on Windows via the command prompt. Once the server has started up, you can copy the URL and paste it in a browser.
Follow the tutorial link to learn about Grails or click on the View Source for Controller/View links to see the underlying code for whatever page you are currently on.