gregbell/active_admin — pull request #623 by ZequeZ (2011-10-14 20:19:14+00:00)
Title: This allows ActiveAdmin::ResourceController::Sorting to sort by a column in another table

The previous behavior always appended the current table name at the beginning of the column.
With this patch it only appends the current table name if the column was given without any specific table.

So now when you can call something like this:

column :name, sortable: 'people.name'

It works as expected. Though when loading the model it has to be joined to the other table, of course.