Story 4: Develop scaffolding code for managing `Rule` entity

[ebouchut]

Story 4: Develop scaffolding code for managing Rule Entity:

1. Implement the RESTFUL API for Creating a Rule entity to "do" the Spring Data Repository
2. Implement the RESTFUL API for Reading a Rule entity from the existing Spring Data Repository
3. Implement the RESTFUL API for Updating a Rule entity from the existing Spring Data Repository
4. Implement the RESTFUL API for Deleting a Rule entity from the existing Spring Data Repository