title: Active admin customization
body: <p>I have an <code>Event</code> model with field status, which is string so it appears as a <code>text_field</code>. But I have a list of possible statuses and I want to display it as a <code>select</code> box. Also, when I select <code>cancel</code> status for a event it should ask me for the cancellation reason. I am not able to find good tutorial for this.</p>