Untitled

## Model element.rb
class Element < ActiveRecord::Base
end

class Directory < Element
end

## Migration

class CreateElements < ActiveRecord::Migration
  def self.up
    create_table :elements do |t|
      t.string :name
      t.string :type
      t.timestamps
    end
  end

  def self.down
    drop_table :elements
  end
end

## Console
>> d=Directory.create(:name=>"test")
NameError: uninitialized constant Directory
        from /Users/patakijv/.gem/ruby/1.8/gems/activesupport-2.3.2/lib/active_support/dependencies.rb:443:in `load_missing_constant'
        from /Users/patakijv/.gem/ruby/1.8/gems/activesupport-2.3.2/lib/active_support/dependencies.rb:80:in `const_missing'
        from /Users/patakijv/.gem/ruby/1.8/gems/activesupport-2.3.2/lib/active_support/dependencies.rb:92:in `const_missing'
        from (irb):1