Find a user by their username

{
  "data": {
    "id": 0,
    "name": "string",
    "email": "string",
    "role": {
      "id": 0,
      "name": "string",
      "permissions": [
        null
      ],
      "created_at": "2019-08-24T14:15:22Z",
      "updated_at": "2019-08-24T14:15:22Z"
    }
  }
}

{
  "message": "string"
}