Add GET-parameters to experiment redirect.

routes/web.php

@@ -44,5 +44,16 @@ Route::middleware(['web', 'auth'])->group(function() {
  * Redirect to the experiment.
  */
 Route::get('/', function () {
-    return redirect('/experiment/index.html');
+    // Append existing GET-Parameters to the redirect route.
+    // If you know a simpler way for this, let me know.
+    // I couldn't find any for unnamed routes...
+
+    $query = request()->query();
+
+    if ($query)
+        $url = '/experiment/index.html?' . http_build_query($query);
+    else
+        $url = '/experiment/index.html';
+
+    return redirect($url);
 });