The CRUD module is the base of any rapid prototyping module. It helps you to administer data in the backend, while still being quick to create a frontend that closely resembles your prototype. For example, when creating an online shop, your first task is to create a nice looking frontend. Still it would be useful if you could change some things such as product name, description, or ID in the backend. This is where CRUD helps. However, there is no security inside the CRUD module, so anyone can add or delete data. This is where the secure module can help.
You can find the source code of this example in the chapter3/crud-secure
directory.
You should already have added controllers for CRUD editing, as well as an infrastructure for authentication or at least something similar to a user entity. If you do not know about this part, you can read about it at http://www.playframework.org/documentation/1.2/crud.