Story 3: Develop scaffolding code for managing `Rating` entity

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Story 3: Develop scaffolding code for managing Rating entity:

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