```ruby
class CreateUsers < ActiveRecord::Migration
  def change
    create_table :users do |t|
      t.string      :first_name
      t.string      :last_name
      t.references  :position

      t.timestamps
    end
  end
end
```

Add 'email' and 'password_digest' to create_users migration
user
```ruby
class CreateUsers < ActiveRecord::Migration
  def change
    create_table :users do |t|
      t.string      :first_name
      t.string      :last_name
      t.string			:email
      t.string			:password_digest
      t.references  :position

      t.timestamps
    end
  end
end
```
assistant