Simple to-do list with tags, priorities and sharing?

Question

Task Management

Are there similar ones for free? I've looked at a lot, and there's something wrong everywhere. Someone has a paid search by tags, someone has no priorities, and so on.
you need:
-tags and search by them
-normal search
-the ability to work with several people with one sheet
-priorities (at least one).
todoist is perfect, but it lacks collaboration. and in its analogue wedoist just a paid search and no tags.
thanks in advance.

Answer 1

www.mytinytodo.net/ru/
demo
www.mytinytodo.net/demo/

Answer 2

look . However, I'm not sure that it satisfies all the requirements.

Answer 3

emacs/org-mode + github/gollum