1. Interface

Post.fetch # fetch post from remote resources and save to the Post
Post::Tumblr.fetch # fetch post from Tumblr and save to the Post

2. post.rb

# skinnycms/app/models/post.rb

class Post < ActiveRecord::Base
  cattr_accessor :plugins

  def fetch
    plugins.each do |plugin|
      Post.constantize(plugin).fetch
    end
  end
end

3. base.rb

# skinnycms/app/models/post/base.rb

class Post::Base
end

4. init.rb

# skinnycms_wordpress/init.rb

require 'app/models/post/wordpress'
Post.plugins << 'wordpress'

5. wordpress.rb

# skinnycms_wordpress/app/models/post/wordpress.rb

class Post::Wordpress < Post::Base
  def self.fetch
  end
end

6. Usage example, posts_controller.rb

# skinnycms/app/controllers/posts_controller.rb

class PostsController << ApplicationController
  def index
    @posts = Post.all
  end

  def videos
    @posts = Post.where(:post_type => 'video').all
  end

  def posts_from_tumblr
    @posts = Post.where(:source => 'tumblr').all
  end

  def images_from_tumblr
    @posts = Post.where(:source => 'tumblr', :post_type => 'image').all
  end
end