curl --request POST \
  --url https://api.example.com/api/v1/attachments/{board_id}/{card_id} \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: multipart/form-data' \
  --form 'file=<string>'

{
  "card_id": "<string>",
  "created_at": "2023-11-07T05:31:56Z",
  "filename": "<string>",
  "id": "<string>",
  "mime_type": "<string>",
  "original_filename": "<string>",
  "size": 123,
  "uploaded_by": "<string>"
}