```ruby
class AddReleasedAtToEpisode < ActiveRecord::Migration
  def change
    add_column :episodes, :released_at, :timestamp
  end
end
```

Use the same type as the last_build_date
user
```ruby
class AddReleasedAtToEpisode < ActiveRecord::Migration
  def change
    add_column :episodes, :released_at, :datetime
  end
end
```
assistant