Please note the new ActiveModel::Model available in Rails 4 which makes it much easier to create a tableless model. In fact, the code shown in this screencast for the model doesn't actually work fully with Rails 4 presumably because of this change (at least it didn't work for me). For info, see: http://blog.plataformatec.com.br/2012/03/barebone-models-to-use-with-actionpack-in-rails-4-0/
Please note the new ActiveModel::Model available in Rails 4 which makes it much easier to create a tableless model. In fact, the code shown in this screencast for the model doesn't actually work fully with Rails 4 presumably because of this change (at least it didn't work for me). For info, see: http://blog.plataformatec.com.br/2012/03/barebone-models-to-use-with-actionpack-in-rails-4-0/