Souke/console/migrations/m180314_081214_add_champs_etablissement.php

<?php

use yii\db\Migration;
use yii\db\Schema;

class m180314_081214_add_champs_etablissement extends Migration {

    public function up() {
        $this->addColumn('etablissement', 'type', Schema::TYPE_STRING);
    }

    public function down() {
        $this->dropColumn('etablissement','type');
    }
}