allo/app/Http/Controllers/Controller.php

<?php

namespace App\Http\Controllers;

use App\Model\Subscriber;
use Illuminate\Foundation\Bus\DispatchesJobs;
use Illuminate\Routing\Controller as BaseController;
use Illuminate\Foundation\Validation\ValidatesRequests;
use Illuminate\Foundation\Auth\Access\AuthorizesRequests;

class Controller extends BaseController
{
    use AuthorizesRequests, DispatchesJobs, ValidatesRequests;

    public function updateCity()
    {
        $subscribers = Subscriber::all();

        foreach ($subscribers as $key => $a) {
            $a->unit_no = strtoupper($a->unit_no);
            $a->building_name = strtoupper($a->building_name);
            $a->street = strtoupper($a->street);
            $a->city = strtoupper($a->city);
            $a->state = strtoupper($a->state);
            $a->save();
        }

        return "Done standardize city in DB";
    }
}