Users

column name	datatype	details
id	integer	not null, pk
username	string	not null, indexed
password digest	string	not null
session token	string	not null, indexed

index on username and session token(both unique)

stories

column name	datatype	details
id	integer	not null, pk
title	string	not null
body	string	not null
author_id	integer	not null, indexed

index on author_id (foreign key)

Comments

column name	datatype	details
id	integer	not null, pk
body	string	not null
author_id	integer	not null, indexed
story_id	integer	not null, indexed
parent_comment_id	integer	maybe indexed?

index on author_id and story_id(foreign keys) parent_comment_id can be null not sure if it needs index

Likes

column name	datatype	details
id	integer	not null, pk
likeable	references	polymorphic, indexed

comments and stories will have a polymorphic assoc. with likes as likeable