find_nth_from_last

# File activerecord/lib/active_record/relation/finder_methods.rb, line 564
    def find_nth_from_last(index)
      if loaded?
        @records[-index]
      else
        relation = if order_values.empty? && primary_key
                     order(arel_attribute(primary_key).asc)
                   else
                     self
                   end

        relation.to_a[-index]
        # TODO: can be made more performant on large result sets by
        # for instance, last(index)[-index] (which would require
        # refactoring the last(n) finder method to make test suite pass),
        # or by using a combination of reverse_order, limit, and offset,
        # e.g., reverse_order.offset(index-1).first
      end
    end