rails/rails — pull request #15753 by eileencodes (2014-06-16 15:55:55+00:00)
Title: Fixes #15671 reflection strings now work as keys

This was fixed on master by #14675 but could not be backported because when the branch was made `_reflect_on_association` didn't exist so grabbing those changes would leave `_reflection_on_association` with the same issue.

This fixes #15671 - where string based keys don't work on nested associations.