Add some error state pages and installer fixes

app/Http/Controllers/HomeController.php

@@ -3,6 +3,7 @@
 namespace App\Http\Controllers;
 
 use App\Models\User;
+use Illuminate\Database\QueryException;
 
 class HomeController extends AppBaseController
 {
@@ -11,7 +12,12 @@ class HomeController extends AppBaseController
      */
     public function index()
     {
-        $users = User::orderBy('created_at', 'desc')->take(4)->get();
+        try {
+            $users = User::orderBy('created_at', 'desc')->take(4)->get();
+        } catch (QueryException $e) {
+            return view('system/errors/not_installed');
+        }
+
         return $this->view('home', [
             'users' => $users,
         ]);