As an person in general I have to keep track of a lot of todo's. I've used everything under the sun to track them. Todoist, Wunderlist, Microsoft Todos, trello, etc...
But nothing was ever as good as a simple piece of paper. Just write down stuff and freeform it. Until I ran across todo.txt.
Its:
- Simple
- Easy
- Programmable
See: http://todotxt.org/