Clicking a sortable column on a nested resource redirects to resource

[knoopx]

ActiveAdmin.register Artist do
    belongs_to :genre, :optional => true

    index do
        column :name, :sortable => :name
    end
end

If I visit /genres/1/artists and click on the Name column you get redirected to /artists?order=name_asc

[gregbell]

Fixed on master.