Errors for STI models (undefined method for paths)

I have models:

• Topic < ActiveRecord::Base
• Topics::News < Topic
• Topics::Article < Topic

The $ rails generate administrate:install created following routes:

# config/routes.rb
# ...
  namespace :admin
    resources :topics
    root to: 'topics#index'
  end

And /admin/ had given me following error:

undefined method `admin_topics_article_path' for #<#<Class:0x007fb0bbf85e30>:0x007fb0c7d159f0>
Did you mean?  admin_topics_path

I think it's problem with how Administrate or Rails handles single table inheritance and model_name of STI models.

My temporary workaround:

class Topic < ActiveRecord::Base
  def self.model_name
    return super if self == Topic
    Topic.model_name
  end
end

Start with config/routes.rb and the /admin/ entry point, then reproduce the undefined admin_topics_article_path error using the Topic, Topics::News, and Topics::Article STI models. Done means the admin topics pages resolve their generated paths without the reported error while preserving the base Topic routing behavior.