```ruby
class CreateStates < ActiveRecord::Migration[5.0]
  def change
    create_table :states do |t|
      t.string :name, null: false
      t.string :display_name, null: false
      t.timestamps
    end
  end
end
```

Remove timestamps from states migration
user
```ruby
class CreateStates < ActiveRecord::Migration[5.0]
  def change
    create_table :states do |t|
      t.string :name, null: false
      t.string :display_name, null: false
    end
  end
end
```
assistant