Update ruby-activerecord3 package to 3.0.4.

* More strict dependency reflect gemspec's description.

*Rails 3.0.4 (unreleased)*

* Added deprecation warning for has_and_belongs_to_many associations where the join table has
  additional attributes other than the keys. Access to these attributes is removed in 3.1.
  Please use has_many :through instead. [Jon Leighton]

*Rails 3.0.3 (November 16, 2010)*

* Support find by class like this: Post.where(:name => Post)

*Rails 3.0.2 (November 15, 2010)*

* Dramatic speed increase (see: http://engineering.attinteractive.com/2010/10/arel-two-point-ohhhhh-yaaaaaa/) [Aaron Patterson]

* reorder is deprecated in favor of except(:order).order(...) [Santiago Pastorino]

* except is now AR public API

    Model.order('name').except(:order).order('salary')

  generates:

    SELECT * FROM models ORDER BY salary

  [Santiago Pastorino]

* The following code:

    Model.limit(10).scoping { Model.count }

  now generates the following SQL:

    SELECT COUNT(*) FROM models LIMIT 10

  This may not return what you want.  Instead, you may with to do something
  like this:

    Model.limit(10).scoping { Model.all.size }

  [Aaron Patterson]

(taca)