docker-php-ext-install ... mysqli pdo_mysql ...
.docker-php-ext-install ... mysql pdo_mysqli ...
.<?= $form->field($model, 'category_id')->textInput(['maxlength' => true]) ?>
<?= $form->field($model, 'category_id')->dropDownList(Category::find()->select(['name', 'id'])->indexBy('id')->column()) ?>