Unescaping HTML on ActiveAdmin Pages
By default, an ActiveAdmin page, either show or index, will escape any HTML in a field that it displays. This is generally good behavior, but if you have an HTML field that’s supposed to have HTML in it, it will be displayed fully escaped, with the < and > tags mucking things up in all their glory. If you have a field that’s supposed to have HTML in it and you take care of cleaning and sanitizing it already (like on save), you can get around this feature like so.