[26/10/2022]: Backend API [feat] - Database model for course exercises

[RealRichi3]

Sub issue from #5

Description

For the backend API for MOOCs platform, there should be exercises for each course with each course could having multiple videos under it and multiple exercises too.

There should be a model for the exercises, a couple of exercise should be available for each course.
These courses should have a one to many relationship with the exercises belonging to it

• Each course should have multiple videos,
• Each course should have multiple exercises,
• Each exercise should have multiple questions,

What I would work on

• Add schema model for questions
• Add schema model for exercises
• Add relation for exercises to questions.
• Add relations for course to exercises.
• Add relations for course to videos

[RealRichi3]

@BatoolMM for the exercises attached to the courses, will they be in form of quizzes with multiple options?