curl --request GET \
  --url https://api.opal.dev/v1/groups/users/{user_id} \
  --header 'Authorization: Bearer <token>'

{
  "next": "cD0yMDIxLTAxLTA2KzAzJTNBMjQlM0E1My40MzQzMjYlMkIwMCUzQTAw",
  "previous": "cj1sZXdwd2VycWVtY29zZnNkc2NzUWxNMEUxTXk0ME16UXpNallsTWtJ",
  "results": [
    {
      "full_name": "Jake Barnes",
      "user_id": "29827fb8-f2dd-4e80-9576-28e31e9934ac",
      "group_id": "1b978423-db0a-4037-a4cf-f79c60cb67b3",
      "expiration_date": "2022-01-23T04:56:07.000Z",
      "email": "jake@company.dev"
    },
    {
      "full_name": "Brett Ashley",
      "user_id": "7646aa9a-e2ee-4eb5-8c62-91f29038a373",
      "group_id": "1b978423-db0a-4037-a4cf-f79c60cb67b3",
      "expiration_date": "2022-02-03T12:33:02.000Z",
      "email": "brett@company.dev"
    }
  ]
}