curl --request POST \
  --url https://api.meetcampfire.com/ca/api/v1/custom-fields \
  --header 'Authorization: <api-key>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "name": "<string>",
  "label": "<string>",
  "field_type": "text",
  "options": "<unknown>",
  "is_required": true,
  "display_order": -1,
  "is_active": true
}
'

{
  "id": 123,
  "app": "<string>",
  "model": "<string>",
  "name": "<string>",
  "label": "<string>",
  "field_type": "text",
  "created_at": "2023-11-07T05:31:56Z",
  "updated_at": "2023-11-07T05:31:56Z",
  "last_modified_at": "2023-11-07T05:31:56Z",
  "is_deleted": false,
  "deleted_at": "2023-11-07T05:31:56Z",
  "options": "<unknown>",
  "is_required": true,
  "display_order": -1,
  "is_active": true
}