title: Create user group using RBAC API?
body: <p>I can't find documentation on how to create user group on Kubernetes with <code>yaml</code> file. I'd like gather some authenticated users in group using their e-mail accounts.</p>
  
  <p>I'd like to write in <code>yaml</code> something like :</p>
  
  <pre><code> kind: GoupBinding
   apiVersion: rbac.authorization.k8s.io/v1beta1
   metadata:
     name: "frontend-developers"
     namespace: development
  subjects:
  - kind: User
    name: a@xyz.com,vv@xyz.com
    apiGroup: ""
  </code></pre>