Provide explanation for onboarding-carts folder

README.md

@@ -8,6 +8,7 @@ Maintained examples are expected to be updated with every keptn release, to use
 
 |Name | Description | Notable Features Used | Complexity Level|
 ------------- | ------------- | ------------ | ------------ |
+| **onboard-carts** | This example builds on [keptn 0.2.0](https://github.com/keptn/keptn/tree/0.2.0) and is required to demonstrate the [onboarding of a service use case](https://keptn.sh/docs/0.2.0/usecases/onboard-carts-service/). | - | Beginner |
 | [**Sockshop**](https://github.com/keptn-sockshop) | This example builds on [keptn 0.1.0](https://github.com/keptn/keptn/tree/0.1.0) and provides four use cases to explore the functionality of keptn. | Kubernetes, Dynatrace, Jenkins, Istio, Ansible Tower | Intermediate |
 
 > Note: Please add examples that are maintained to the list above.
@@ -18,4 +19,3 @@ in this directory, and what examples should contain. -->
 ### Contributing
 
 Please see [CONTRIBUTING.md](CONTRIBUTING.md) for instructions on how to contribute.
-