How do I change the session cache type (to use og instead of memory sessions)
Just set the following in your config or run.rb:
Nitro::Session.cache_type = :og
:drb :file :memcached :memory
Please note that if you use the Og store, you have to initialize the Og store after setting the Session type to Og:
Nitro::Session.cache_type = :og Og.setup(:store => ....)
The order is important here, first the session type, then the Og store.