SearchObserver with no update_index

gistfile1.rb

class SearchObserver < ActiveRecord::Observer
  observe :topic, :post, :user, :category

  def after_save(obj)
    if obj.class == Post && obj.cooked_changed?
      search_data = obj.scrubbed_html << " " << obj.topic.title
      search_data << " " << obj.topic.category.name if obj.topic.category
      ObserverSearchData.new(obj, search_data).update_index
    end
    if obj.class == User && (obj.username_changed? || obj.name_changed?)
      search_data = obj.username.dup << " " << (obj.name || "")
      ObserverSearchData.new(obj, search_data).update_index
    end

    if obj.class == Topic && obj.title_changed?
      if obj.posts
        post = obj.posts.where(post_number: 1).first
        if post
          search_data = post.scrubbed_html << " " << obj.title
          search_data << " " << obj.category.name if obj.category
          ObserverSearchData.new(post, search_data).update_index
        end
      end
    end

    if obj.class == Category && obj.name_changed?
      ObserverSearchData.new(obj, obj.name).update_index
    end
  end
end