Organize scattered PHP files into scripts/ and tests/ directories

scripts/add_columns.php

@@ -0,0 +1,8 @@
+<?php
+require '../vendor/autoload.php';
+require '../config.php';
+ = new PDO('sqlite:' . DB_PATH);
+->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
+try {
+    ->exec('ALTER TABLE items ADD COLUMN id_code TEXT');
+    echo id_code