restore composer.json, add mysqli extension

app/Services/API/CalculaionService.php

@@ -0,0 +1,17 @@
+<?php
+
+namespace App\Services\API;
+
+
+class CalculationService
+{
+    public function __construct()
+    {
+        echo "Empty func";
+    }
+
+    public function get_file(int $kv, int $f): string
+    {
+        return "salom";
+    }
+}