Значение настройки Laravel Backpack на поле

$this->crud->addField([
'label' => "Department",
'type' => 'select_multiple',
'name' => 'departments',
// the method that defines the relationship in your Model
'entity' => 'departments', // the method that defines the relationship in your Model
'attribute' => 'department_name', // foreign key attribute that is shown to user
'model' => "App\Models\DepartmentNames", // foreign key model
'pivot' => true, // on create&update, do you need to add/delete pivot table entries?
]);

Когда я публикую массив «отдел» пуст,

<select class="form-control" name="department[]" multiple="">
<option value="">-</option>
<option value="">Account Management</option>
<option value="">Services</option>
<option value="">Customers</option>
<option value="">Technical</option>
</select>

Схема для отделаNames

- id
-department_name