Fixed bug causing error 500 on production

Some PHP version or configuration were causing this error.

On app.blade.php of local branch, I could use "$usedItems ? :"
even if $usedItems were null, but I had to check an "isset" to the production.

On HomecController, I had to change the "object" parameter of getUsername
to "\Illuminate\Database\Eloquent\Collection" to make it work.

I took the chance to just show the number of itens in use
if it were greater than 0.

app/Http/Controllers/HomeController.php

@@ -55,7 +55,7 @@ class HomeController extends Controller
      *
      * @return void
      */
-    public function getUsername(object $itemUsers, ?int $id)
+    protected function getUsername(\Illuminate\Database\Eloquent\Collection $itemUsers, ?int $id)
     {
         if ($id && !isset($this->activeUsers[$id])) {
             $this->activeUsers[$id] = $this->findName($itemUsers, $id);