Description:

Generates a database migration and updates the model file (if it exists).
Pass the model name, either CamelCased or under_scored, and the event name
as an infinitive.

Examples:

`bin/rails generate active_record:event task complete`

    Generates a migration adding a `completed_at` column to the `tasks`
    table and updates the Task model.

`bin/rails generate active_record:event user confirm --object=email`

    Generates a migration adding an `email_confirmed_at` column to the
    `users` table and updates the User model.