Tasks and sub tasks database structure

[rafoolin]

A Task can have several tasks or nothing(standalone one)
If a parent task is marked as done, all the children will be marked as done as well.

For example:
Task project has 3 other sub-tasks: write documentation, write code, write test.

🟩 Project
    🟩 write documentation.
    🟩 write code.
    🟩 write test.

We can have it like:
🟩 Project
    🟩 write documentation.
    ✅ write code.
    🟩 write test.

or
🟩 Project
    🟩 write documentation.
    ✅ write code.
    ✅ write test.

And
✅ Project
    ✅ write documentation.
    ✅ write code.
    ✅ write test.

Task in database:

type	name
id	uuid
user_id	uuid
category_id	uuid
parent_id	uuid
title	text
date_time	timestamp
done_at	timestamp
created_at	timestamp
updated_at	timestamp
completed	boolean
note	text

[rafoolin]

closed by 238d5b3