updating usage section of readme

Author: tobiasehlert

README.md

@@ -6,3 +6,11 @@ TibiaData Helm charts for deploying into Kubernetes.
 
 [Helm](https://helm.sh) must be installed to use the charts.
 Please refer to Helm's [documentation](https://helm.sh/docs/) to get started.
+
+Once Helm is set up properly, add the repository as follows:
+
+```console
+helm repo add tibiadata https://charts.tibiadata.com
+```
+
+You can then run `helm search repo tibiadata` to see the charts.