Log Message:
Update ruby-activerecord3 pacakge to 3.0.8.

*Rails 3.0.8 (unreleased)*

* Fix various problems with using :primary_key and :foreign_key options in \ 
conjunction with
  :through associations. [Jon Leighton]

* Correctly handle inner joins on polymorphic relationships.

* Fixed infinity and negative infinity cases in PG date columns.

* Creating records with invalid associations via `create` or `save` will no
  longer raise exceptions.