rails/rails — pull request #6533 by jaimeiniesta (2012-05-29 10:51:18+00:00)
Title: Fix pluralize helper to properly handle minus one

Here is a good explanation:
http://neilwhitfield.wordpress.com/2007/10/31/good-question-are-fractions-and-decimals-singular-or-plural/

'If the number one is used, whether it is +/-1, the following noun will be
singular. So it would be -1 apple. We’re talking grammar, not logic; and yes we
say zero apples, probably because zero is thought of as a number that is not
one, even though zero is neither singular nor plural logically.'