Task tracker for one person (not for a development team)?

Question

Task Management

I'm looking for a simple TODO-shku for personal use to maintain a list of all tasks for web projects.
At the moment I'm using a text file with a huge list of tasks (from "fix the link there and there" to "switch to postgre").
I would like to structure the whole thing: break it down into categories and assign a degree of importance.
To get a structure like this:

Проект #1
    Frontend
        — Сделать новый красивый лэндинг
        — Минимизировать html перед
        — Запилить ajax-валидацию всех форм
    Backend
        — Переписать компонент отправки email
        — Добавить подтверждение по sms всех финансовых операций
        ...
    Server
        Переехать с mysql на postgre
        Настроить связку apache-nginx
        Купить ssl-сертификат и настоить https для ЛК
Проект #2
    ...
        ...
        ...
    ...
        ...

It is desirable that there is no binding to dates. Development is not my main occupation, I can sit down at any time and complete tasks according to the list.
It is desirable in the web version, but a desktop version is also possible.
Both cloud and boxed versions are suitable.
Has anyone found something similar?

Answer 1

Another option: trello.com is also good for small teams.
Projects -> boards, sheets -> task branches.

Answer 2

dropbox+sublime+plaintasks