public Result index(Integer projectid) {
   project = Project.find.byId(projectid);
   for (Task task : project.getTasks()) {
     if (folders.containsKey(task.getFolder())) folders.get(task.getFolder()).add(task);
     else folders.put(task.getFolder(), new ArrayList<Task>(Arrays.asList(task)));
   }
   return ok(this);
 }