users

column	datatype	properties
id	integer	null:false
username	string	null:false, index, unique
email	string	null:false, index, unique
password_digest	string	null:false
session_token	string	null:false, index, unique
created_at	datetime	null:false
updated_at	datetime	null:false

• index on username, email, and session_token
• foreign key: has_many posts
• foreign key: has_many likes
• foreign key: has_many comments

posts

column	datatype	properties
id	integer	null:false
author_id	integer	null:false, index
title	string	null:false
body	string	none
url	string	none
created_at	datetime	null:false,
updated_at	datetime	null:false

• index on author_id
• author_id references users
• belongs_to author
• foreign key: has_many likes
• foreign key: has_many comments

comments

column	datatype	properties
id	integer	null:false
commenter_id	integer	null:false, index
post_id	string	null:false, index
body	string	null:false
created_at	datetime	null:false,
updated_at	datetime	null:false

• index on commenter_id and post_id
• commenter_id references users
• post_id references posts
• belongs_to commenter
• belongs_to post

likes

column	datatype	properties
id	integer	null:false
liker_id	integer	null:false, index
post_id	string	null:false, index
created_at	datetime	null:false,
updated_at	datetime	null:false

• index on liker_id and post_id
• liker_id references users
• post_id references posts
• belongs_to liker
• belongs_to post