I’m doing a research for a blogpost. I want to find out what was the
reason behind adding insertion order to hashes in Ruby 1.9.0.
My findings led me to a thread on ruby-list.  It’s in Japanese and
unfortunately, I can’t read it. Translating Matz’ messages using Google
Translate makes me believe it contains some useful information.
Ilya G. in his “Ruby 1.9 Internals: Ordered Hash” article 
mentions that “Ruby mailing list archive is full of heated discussions
on whether a Ruby hash should be an ordered hash”. I think it might be
one of the threads he had in mind.
I’d be very thankful if somebody could tell me if it’s even the thread
I’m looking for and extract key points from it.