Php 如何在Yii2的下拉列表中添加额外选项

我的yii2应用程序中有一个下拉列表，它从数据库表中获取数据。现在，我想在dropdownlist中添加一个额外的选项，其值为1，显示为admin

我当前的下拉列表是：

<?= Html::dropDownLIst('assign_to', null, 
                    ArrayHelper::map(PhCrmUser::findAll(['user_type' => 'executive_manager', 'status' => CrmUser::STATUS_ACTIVE]), 'id',
                       function($model, $defaultValue) {
                          return $model['first_name']." ".$model['last_name'];
                       }
                     ),
                    ['class' => 'form-control', 'prompt' => 'Assign to Manager']
                  )?>

它将输出显示为

<select class="form-control" name="assign_to">
<option value="">Assign to Manager</option>
<option value="8">Matt Demon</option>
<option value="10">Vinit Singh</option>
<option value="14">dsfds sdfsdf</option>
</select>

现在我想在我的dropdownlist中添加一个额外的静态选项，如何在yii中实现它。我的输出应该是这样的

<select class="form-control" name="assign_to">
<option value="">Assign to Manager</option>
<option value="1">Admin</option>
<option value="8">Matt Demon</option>
<option value="10">Vinit Singh</option>
<option value="14">dsfds sdfsdf</option>
</select>

---

只需将其添加到值数组中

<?= Html::dropDownLIst('assign_to', null, 
                ['1' => 'Admin'] + ArrayHelper::map(PhCrmUser::findAll(['user_type' => 'executive_manager', 'status' => CrmUser::STATUS_ACTIVE]), 'id',
                   function($model, $defaultValue) {
                      return $model['first_name']." ".$model['last_name'];
                   }
                 ),
                ['class' => 'form-control', 'prompt' => 'Assign to Manager']
              )?>

---

只需将其添加到值数组中

<?= Html::dropDownLIst('assign_to', null, 
                ['1' => 'Admin'] + ArrayHelper::map(PhCrmUser::findAll(['user_type' => 'executive_manager', 'status' => CrmUser::STATUS_ACTIVE]), 'id',
                   function($model, $defaultValue) {
                      return $model['first_name']." ".$model['last_name'];
                   }
                 ),
                ['class' => 'form-control', 'prompt' => 'Assign to Manager']
              )?>