escape_hstore uses quotation marks around keys and values only if it
seems necessary. However, it currently breaks in the presence of some
non-ASCII characters. Instead of trying to guess exactly which
characters are safe, it seems better to always use quotes.

if they are not defined or delegated.
In this way, we have a performance boost invoking some array methods
which are not defined in CollectionAssociation.

The release date details have been taken from
http://weblog.rubyonrails.org/2012/3/30/ann-rails-3-2-3-has-been-released/