allow emptying server description, closes #442

app/Repositories/ServerRepository.php

@@ -370,7 +370,7 @@ class ServerRepository
         $validator = Validator::make($data, [
             'owner_id' => 'sometimes|required|integer|exists:users,id',
             'name' => 'sometimes|required|regex:([\w .-]{1,200})',
-            'description' => 'sometimes|required|string',
+            'description' => 'sometimes|nullable|string',
             'reset_token' => 'sometimes|required|accepted',
         ]);