This doesn't seem to be working as intended?  Unless I'm missing something.

```
NoMethodError - undefined method `session_class' for ActiveRecord::SessionStore:Module:
   () Users/altonymous/.rvm/gems/ruby-2.0.0-p353@client/bundler/gems/rubycas-client-f1b17063b824/lib/casclient/tickets/storage.rb:32:in `get_session_for_service_ticket'
   () Users/altonymous/.rvm/gems/ruby-2.0.0-p353@client/bundler/gems/rubycas-client-f1b17063b824/lib/casclient/tickets/storage.rb:13:in `process_single_sign_out'
   () Users/altonymous/.rvm/gems/ruby-2.0.0-p353@client/bundler/gems/rubycas-client-f1b17063b824/lib/casclient/frameworks/rails/filter.rb:300:in `single_sign_out'
   () Users/altonymous/.rvm/gems/ruby-2.0.0-p353@client/bundler/gems/rubycas-client-f1b17063b824/lib/casclient/frameworks/rails/filter.rb:28:in `filter'
```