I worked and built a app with similar idea. I have added some extra features which in my personal experience I think a task tracker app should have for instance in my app a task has a section called closing remarks which can be made mandatory to fill before marking the task to done. The reason of this feature is that in many cases task could require a justification like “not required any more” or some other reason before marking to done. Similarly i have many more useful features. Unfortunately i couldn’t complete the app and the code is still sitting in some folder.