Can't create user

I'm getting this error

> Error from server (Forbidden): error when creating "monica-database-user.yaml": admission webhook "vdatabaseuser.kb.io" denied the request: spec.username: Duplicate value: "monica"

With this yaml file:
```
apiVersion: databases.digitalocean.com/v1alpha1
kind: DatabaseUser
metadata:
name: monica-db-user
spec:
databaseCluster:
apiGroup: databases.digitalocean.com
kind: DatabaseClusterReference
name: my-db
username: monica
```
Using version: 0.1.13