Design a social media feed that displays posts from users that a person follows, similar to Twitter or Instagram. The feed should be personalized and show the most recent and relevant posts.

Analyze points below by referring to course materials:

How would you design the data model to store user posts and relationships? $(8$points$)$

How would you fetch and display the feed for a user? $(4$points$)$

How would you ensure the feed is always up$-$to$-$date? $(4$points$)$

How would you handle scalability when the number of users and posts grows exponentially? $(4$points$)$