// $this->request->data
array:3 [▼
  "title" => "abcdefg"
  "body" => "abcdefghsdflösdfklösdfsddfghdfgd"
  "article_type" => array:1 [▼
    "id" => "3"
  ]
]

// $article
Article {#101 ▼
  +"body": "abcdefghsdflösdfklösdfsddfghdfgd"
  +"article_type": Entity {#127 ▼
    +"id": 3
    +"[new]": true
    +"[accessible]": array:1 [▶]
    +"[dirty]": array:1 [▶]
    +"[original]": []
    +"[virtual]": []
    +"[errors]": []
    +"[invalid]": []
    +"[repository]": "ArticleTypes"
  }
  +"[new]": true
  +"[accessible]": array:1 [▶]
  +"[dirty]": array:2 [▶]
  +"[original]": []
  +"[virtual]": []
  +"[errors]": array:1 [▶]
  +"[invalid]": array:1 [▶]
  +"[repository]": "Articles"
}