supermodel doesnt support current active_support?

[mooreniemi]

main » require 'supermodel'
LoadError: cannot load such file -- active_support/core_ext/class/inheritable_attributes
from /Users/Alex/.rvm/rubies/ruby-2.2.2/lib/ruby/site_ruby/2.2.0/rubygems/core_ext/kernel_require.rb:121:in `require'