title: Rails 2.3 STI return all child classes
body: <p>I am using standard STI and want to create an input select on a form whose options are all child type of the parent class. So I'd like Parent.select_options to return ['Child1','Child2','Child3']</p>
  
  <pre><code>class Parent &lt; ActiveRecord::Base
    # kinda what I'd like except the descendants method is undefined in rails 2.3
    def self.select_options
      descendants.map{ |c| c.to_s }.sort
    end
  end
  
  class Child1 &lt; Parent
  end
  
  class Child2 &lt; Parent
  end
  
  class Child3 &lt; Parent
  end
  </code></pre>
  
  <p>view.html.haml</p>
  
  <pre><code>= f.input :parent_id, :as =&gt; :select, :collection =&gt; Parent.select_options, :prompt =&gt; true
  </code></pre>
  
  <p>UPDATE</p>
  
  <p>Thanks to @nash and @jdeseno just need to add the following initializer using @jdeseno method:</p>
  
  <pre><code>%w[parent child1 child2 child3].each do |c|
    require_dependency File.join("app","models","#{c}.rb")
  end
  </code></pre>