Add testing section to docs

Signed-off-by: Stefan Prodan <stefan.prodan@gmail.com>

README.md

@@ -1,5 +1,9 @@
 # flux2-multi-tenancy
 
+[![test](https://github.com/fluxcd/flux2-multi-tenancy/workflows/test/badge.svg)](https://github.com/fluxcd/flux2-multi-tenancy/actions)
+[![e2e](https://github.com/fluxcd/flux2-multi-tenancy/workflows/e2e/badge.svg)](https://github.com/fluxcd/flux2-multi-tenancy/actions)
+[![license](https://img.shields.io/github/license/fluxcd/flux2-multi-tenancy.svg)](https://github.com/fluxcd/flux2-multi-tenancy/blob/main/LICENSE)
+
 This repository serves as a starting point for managing multi-tenant clusters with Git and Flux v2.
 
 ![](docs/img/flux2-multi-tenancy.png)
@@ -421,3 +425,13 @@ With the above configuration, the Flux instance running on the staging cluster w
 * create the tenant Git credentials Kubernetes secret in the tenant namespace
 * clone the tenant repository using the supplied credentials
 * apply the `./staging` directory from the tenant's repo using the tenant's service account
+
+## Testing
+
+Any change to the Kubernetes manifests or to the repository structure should be validated in CI before
+a pull request is merged into the main branch and synced on the cluster.
+
+This repository contains the following GitHub CI workflows:
+
+* the [test](./.github/workflows/test.yaml) workflow validates the Kubernetes manifests and Kustomize overlays with kubeval
+* the [e2e](./.github/workflows/e2e.yaml) workflow starts a Kubernetes cluster in CI and tests the staging setup by running Flux in Kubernetes Kind