This provides a super simple wrapper around Rails.cache.fetch to make it super
easy to grab objects from the database using caching. It also handles the glory that is
unmarshalling objects from memory into classes lazy/auto loaded from Rails. (Extra fun in development!)

If you need to manually use Rails.cache.something and need the key, 
call +cached_find_key_for( *args )+ using the same *args you would use on the cached_find.
 
This works in Rails 2.3 and newer. (probably 2.1+, but 2.3+ for sure.)

This should work with any cache backend, but I've only used it with Memcache. Results may vary, and
patches are appreciated if any problems are found :)

=== Usage

Basically this works the same as ActiveRecord#find and friends, 
except you add cached_ in front of it.

  User.cached_find( 1 ) 
  User.cached_find_all_by_foo( 'bar', :include => :baz, :limit => 2 )