Allow max_uses to be empty.

app/Http/Requests/StoreInput.php

@@ -43,7 +43,7 @@ class StoreInput extends FormRequest {
         return [
             "id" => 'required|unique:inputs',
             "id_length" => 'required|integer|gt:0',
-            "max_uses" => 'integer|gte:0',
+            "max_uses" => 'nullable|integer|gte:0',
             "increments" => Rule::in(Input::INCREMENT_MODES),
             "data" => $this->get('format') === 'json' ? 'required|JSON' : 'required'
         ];