Update StudyController.php

* bugfix on duplicate study: when you duplicate and you have an interview with a created token, now it's not duplicated (caused errors)

app/Http/Controllers/StudyController.php

@@ -21,6 +21,7 @@ use Illuminate\Http\JsonResponse;
 use Illuminate\Http\RedirectResponse;
 use Illuminate\Http\Request;
 use Illuminate\Http\Response;
+use Illuminate\Support\Facades\Log;
 use Illuminate\View\View;
 use Image;
 use Storage;
@@ -81,6 +82,13 @@ class StudyController extends Controller
 
             } else if ($relationName == "tokens") {
 
+                foreach($values as $index => $token ) {
+                    if($token->author == 0) {
+                        unset($values[$index]);
+                    }
+                }
+
+
                 $copy->{$relationName}()->attach($values);
             }
         }