yii composer install

config/db.php

@@ -0,0 +1,9 @@
+<?php
+
+return [
+    'class' => 'yii\db\Connection',
+    'dsn' => 'mysql:host=localhost;dbname=yii2basic',
+    'username' => 'root',
+    'password' => '',
+    'charset' => 'utf8',
+];