Schema

users

column name	data type	details
id	int	not null, primary_key
email	string	not null, indexed, unique
phone number	int	not null, indexed, unique
password_digest	string
session_token	string	not null, indexed

contacts

column name	data type	details
id	int	not null, primary key
first name	string	not null
last name	string
phone number	integer	not null, unique
interval	date object	not null, default 1 day
user_id	int	not null, foreign key

• user_id points to users table

Reasons

column name	data type	details
id	int	not null, primary key
body	text	not null, character limit of 180
sent	boolean	not null
contact_id	integer	not null, foreign key indexed

+contact_id points to the contacts table