Add lib-noir and database dependencies.
Create Users schema.

* wire up database connection
* function to create users table
* have git ignore REPL artifact and sqlite database
User registration.

* basic registration page route and form that stores ID in session.
* show user ID on home page.
* validate registration form fields.
* style error messages.
* show registration link on home page if no user session.
* create user in database upon registration.
* error checking for duplicate user ID's.