Interface or Not: Creating Polymorphic Model Relationships in Ruby on Rails Dynamically

Please bear with me for a moment as I try to explain exactly what I would like to achieve.

In my Ruby on Rails application, I have a model called Page.

It is a web page.

I would like to enable user to arbitrarily attach components to the page. Some examples of "components" are Picture, PictureCollection, Video, VideoCollection, Background, Audio, Form, Comments.

I currently have a direct link between page and image:

class Page < ActiveRecord::Base
  has_many :pictures, :as => :imageable, :dependent => :destroy
end

class Picture < ActiveRecord::Base
  belongs_to :imageable, :polymorphic => true
end

      

        
        
        
      

    

This relationship allows the user to associate an arbitrary number of images with the page. Now, if I want to provide multiple collections, I need an additional model:

class PictureCollection < ActiveRecord::Base
  belongs_to :collectionable, :polymorphic => true
  has_many :pictures, :as => :imageable, :dependent => :destroy
end

      

        
        
        
      

    

And change the page to link to the new model:

class Page < ActiveRecord::Base
  has_many :picture_collections, :as => :collectionable, :dependent => :destroy
end

      

        
        
        
      

    

The user can now add any number of image collections to the page.

However, this is still very static with respect to the link: picture_collections in the page model. If I add another "component" like: video_collections, I need to declare another link on the page for that type of component.

So my question is:

Do I need to add a new link for each component type or is there some other way? In ActionScript / Java, I declare an interface Component and force all components to implement that interface, then I can only have one attribute: components that contain all dynamically linked model objects.

This is Rails, and I'm sure there is a great way to achieve this, but its complicated Google approach. Perhaps you good people have some wise suggestions. Thanks in advance for taking the time to read and answer this.