rails/rails — pull request #5364 by carlosantoniodasilva (2012-03-10 01:28:32+00:00)
Title: Active model serialization :include returning string keys

Some time ago [this was fixed related to the `:methods` option](https://github.com/rails/rails/commit/ad9f968c4a4639bdc5e0a6e71189a1756c959ca3), now I noticed the same issue with `:include`. To make the api more consistent, this changes it to return string keys as well.

It also removes the usage of `Array#wrap` in serialization module.