Added City model, resource and its API.

app/Models/City.php

@@ -0,0 +1,11 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Factories\HasFactory;
+use Illuminate\Database\Eloquent\Model;
+
+class City extends Model
+{
+    use HasFactory;
+}