How homework history works?

1. Mentor adds homework task to the lesson (using post endpoint for add homework task)
2. Student gets homework and starts doing it
3. If he wants to save his progress without submitting homework, he pushs save button (saving homework with flag isSent = false)
4. When he sends his homework to mentor for review, the flag becomes isSent = true (using put endpoint for update homework)
5. The mentor evaluetes student's homework, and if mark is not satisfactory, the student can re-send homework (using put endpoint for update homework)
6. When a student resubmits homework, the new homework replaces the old one and the old homework is added to the homework history