curl --request POST \
  --url https://api.rownd.io/applications/{app}/groups/{group}/members \
  --header 'Content-Type: application/json' \
  --header 'x-rownd-app-key: <api-key>' \
  --header 'x-rownd-app-secret: <api-key>' \
  --data '{
  "user_id": "user_fbylaq38591cghym5pabupj2",
  "roles": [
    "owner",
    "editor"
  ],
  "state": "active"
}'

{
  "id": "member_dnn5g4e3q6aptail2gr43kpj",
  "user_id": "user_fbylaq38591cghym5pabupj2",
  "roles": [
    "owner",
    "editor"
  ],
  "state": "active",
  "invited_by": "<string>",
  "added_by": "<string>",
  "profile": {
    "user_id": "user_a7b53gwdaml5jt7t71442nt7",
    "email": "gary@foo.com",
    "first_name": "Gary",
    "last_name": "Jackson"
  },
  "group_id": "group_ig42thhwf4cig25o7t9jtlyu"
}