Update README.md

Author: snorwin

README.md

@@ -55,4 +55,44 @@ if err = (&pod.Webhook{}).SetupWebhookWithManager(mgr); err != nil {
     setupLog.Error(err, "unable to create webhook", "webhook", "Pod")
     os.Exit(1)
 }
+```
+
+## Examples
+### Mutating admission webhook using `MutateObjectByFunc`
+```go
+package pod
+
+import (
+	"context"
+	
+	corev1 "k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/runtime"
+	"sigs.k8s.io/controller-runtime/pkg/log"
+	"sigs.k8s.io/controller-runtime/pkg/manager"
+	"sigs.k8s.io/controller-runtime/pkg/webhook/admission"
+
+	"github.com/snorwin/k8s-generic-webhook/pkg/webhook"
+)
+
+type Webhook struct {
+	webhook.MutatingWebhook
+}
+
+func (w *Webhook) SetupWebhookWithManager(mgr manager.Manager) error {
+	return webhook.NewGenericWebhookManagedBy(mgr).
+		For(&corev1.Pod{}).
+		Complete(w)
+}
+
+func (w *Webhook) Mutate(ctx context.Context, req admission.Request) admission.Response {
+	return webhook.MutateObjectByFunc(ctx, req, func(ctx context.Context, request admission.Request, object runtime.Object) error {
+		_ = log.FromContext(ctx)
+
+		pod := object.(*corev1.Pod)
+		// TODO add your programmatic mutation logic here
+		object = pod
+		
+		return nil
+	})
+}
 ```