Ourspace, a clone of Facebook, allows signed-up users to post pictures and text, comment on posts, edit/delete comments, like posts and comments, friend other users, and customize their profile page.
Hey Jaspreet! Design docs looking good, some suggestions below:
MVP
Everything looks good here!
Schema
no need for a liker_id or comment_id on the posts table as posts will have many likes and comments
comments table should have a post_id for now. Consider eventually creating functionality for comments to be able to be commented on also (Reddit Clone is a great project to reference for that).
likes table should have a polymorphic association so a user can like either a comment or a post. Take a look at the Rails documentation on polymorphic associations.
friendships table should have 2 foreign keys that reference the friend requester and the friend request receiver. Consider adding a pending boolean column for users to be able to accept or decline friend requests.