Note update of Ruby on Rails package to 3.1.8.

devel/ruby-activesupport31 3.1.8
devel/ruby-activemodel31 3.1.8
www/ruby-actionpack31 3.1.8
databases/ruby-activerecord31 3.1.8
www/ruby-activeresource31 3.1.8
mail/ruby-actionmailer31 3.1.8
devel/ruby-railties31 3.1.8
www/ruby-rails31 3.1.8

(taca)