searchable: don't automatically include id, created_at, updated_at.

Don't make search methods on models call super in order to search
certain default attributes (id, created_at, updated_at). Simplifies some
magic.

app/models/favorite_group.rb

@@ -26,8 +26,7 @@ class FavoriteGroup < ApplicationRecord
     end
 
     def search(params)
-      q = super
-      q = q.search_attributes(params, :name, :is_public, :post_ids)
+      q = search_attributes(params, :id, :created_at, :updated_at, :name, :is_public, :post_ids)
 
       if params[:name_matches].present?
         q = q.name_matches(params[:name_matches])