document running locally

Author: maxbischoff

.gitignore

@@ -2,3 +2,4 @@ build/
 
 # vim swap files
 .*.sw*
+clouds.yaml

README.md

@@ -4,3 +4,14 @@ This is an [ExternalDNS provider](https://github.com/kubernetes-sigs/external-dn
 This projects externalizes the yet in-tree [OpenStack Designate provider](https://github.com/kubernetes-sigs/external-dns/tree/master/provider/designate).
 
 ### 🌪 This project is in a very early stage and likely does not do what you expect!
+
+## Development
+
+To run the webhook locally, you'll need to create a [clouds.yaml](https://docs.openstack.org/python-openstackclient/pike/configuration/index.html#clouds-yaml)
+file and put it in one of the standard-locations.
+Then set the cloud to be used in the `OS_CLOUD` environemnt variable.
+You can then start the webhook server using:
+
+```sh
+go run cmd/webhook/main.go
+```