title: How to use a find_by_sql query for an ActiveAdmin index page?
body: <p>I'm using active admin on a project.  I have a request to create a new resource and was given a complex SQL query to use - which connects to a different DB.  All is good - however, I'm somewhat new to ActiveAdmin and curious how to get the index page to use my custom query vs. the default resource.</p>
  
  <p>I just need a nudge/sample to see how to override this default activity.</p>