```ruby
class CreateAliases < ActiveRecord::Migration
  def change
    create_table :aliases do |t|
      t.string :name
      t.references :document, index: true, foreign_key: true

      t.timestamps null: false
    end
  end
end
```

Clean up alias migration script
user
```ruby
# Encoding: utf-8
# Create alias
class CreateAliases < ActiveRecord::Migration
  def change
    create_table :aliases do |t|
      t.string :name
      t.references :document, index: true, foreign_key: true

      t.timestamps null: false
    end
  end
end
```
assistant