'CheckAdmin' => [
        AppHttpMiddlewareCheckUserIfAdmin::class,
  ],

'CheckAdmin' => AppHttpMiddlewareCheckUserIfAdmin::class,

Route::group(['middleware' => ['CheckAdmin']], function () {
      Route::get('/admin', [
        'uses' => 'AdminController@index',
        'as' => 'adminpage'
    ]);
  });

<?php

 namespace AppHttpMiddleware;

 use Closure;

 class CheckUserIfAdmin
  {

    public function handle($request, Closure $next)
    {

        if(Session::has('ad_id') === false):
           return redirect()->route('admin.login');
        endif;


        return $next($request);
    }