How to pass ActiveRecord model class to Resque

Let's say I have the following Resque job:

class Archive
  @queue = :file_serve

  def self.perform(repo_id, branch = 'master')
    repo = Repository.find(repo_id)
    repo.create_archive(branch)
  end
end

What if I wanted to make this more generic by passing an object id and the object's class so that I can do something like this:

class Archive
  @queue = :file_serve

  def self.perform(object_class, object_id, branch = 'master')
    object = object_class.find(object_id)
    object.create_archive(branch)
  end
end

This doesn't work, obviously, and I don't have a sense for what I should be doing, so if anyone can give some guidance, that would be really appreciated!