Create a new group

Example request

{
  "description": "Viewers Group",
  "name": "Viewers",
  "expires_at": 1576300370,
  "org_default_role": "admin",
  "org_roles": {
    "1a5e612e-4d64-45fe-aa3e-afba5cf3b9bf": "viewer",
    "fd6d6662-732b-4c4b-8331-051178994384": "admin"
  }
}