By now you should be familiar with basic sinatra apps and creating simple websites. This problem will give you a chance to demonstrate your proficiency with the web by writing code for controllers, authentication, views, and basic HTML forms with a little bit of CSS. We're going full CRUD and building a simple event-management application.

The problem is broken into 4 parts. You will need to complete each part to move on. We've given approximate timing for each part. If you find you are taking a lot longer be sure to ask questions.

Authentication is a central concern of most web applications. We're going to start by creating a simple app that does nothing more than authenticate a user.

You have an empty User model and a database with a users table. Add validations to the User model which guarantee the following:

1. Every user has an email
2. Every user's email is unique
3. Every email looks like * @ *.*
4. Every user has a password

You should not store the user's password directly in the database.

Create views to allow a user to:

1. Sign up as a new user
2. Log in as an existing user
3. Log out as an existing user

We have users and events. Users can attend many events and an event can be attended by many users. Events are user-created, too, so an event belongs to a user and a user can create multiple events.

We've already defined the three models for you. You'll need to create the associations between them.

The User model should have two associations on it:

1. user.created_events should return the list of events created by the user
2. user.attended_events should return the list of events the user is attending or has attended

To be clear, created_events and attended_events should return completely different results (we are not asking you to create an alias).

To help you along your way, we recommend reviewing the ActiveRecord documentation, specifically the available options for the association methods you'll be using.

With user authentication in place, create pages which let the user create new events, show their created events, edit events, and destroy events.

On the page that lists all the events created by the user, add the form for creating a new event. Use AJAX on this form so that when a user adds a new event, that new event is appended to the list of created events without refreshing the page.