hack truncate in ruby 1.8.7 compability issue

add follows code into rails app environment.rb and restart the service
# http://rails.lighthouseapp.com/projects/8994/tickets/867-undefined-method-length-for-enumerable

class String
def chars
ActiveSupport::Multibyte::Chars.new(self)
end
alias_method :mb_chars, :chars
end
##
module ActionView
module Helpers
module TextHelper
def truncate(text, length = 30, truncate_string = "...")
if text.nil? then return end
l = length - truncate_string.chars.to_a.size
(text.chars.to_a.size > length ? text.chars.to_a[0...l].join + truncate_string : text).to_s
end
end
end
end