title: Unable to expire_action on Rails
body: <p><strong>tl;dr</strong></p>
  
  <p>My <code>expire_index</code> method below is getting called, I see the <code>puts</code> in the logs. However, when I refresh the page is the stale version.</p>
  
  <p><strong>note:</strong> I am using rails_admin for updating the models. But have also noticed the same behavior using rails console directly.</p>
  
  <p>Thanks for your help. Much appreciated!</p>
  
  <p><strong>details</strong></p>
  
  <p><strong><code>app/controllers/posts_controller.rb</code></strong></p>
  
  <pre><code>class PostsController &lt; ApplicationController
    caches_action :index
    cache_sweeper :post_sweeper
  
    def index
      @posts = Post.published
    end
  
    def show
      @post = Post.find(params[:id])
     end
  end
  </code></pre>
  
  <p><strong><code>app/sweepers/post_sweeper.rb</code></strong></p>
  
  <pre><code>class PostSweeper &lt; ActionController::Caching::Sweeper
    observe Post
  
    def after_save(post)
      puts "======================"
      puts "      AFTER SAVE      "
      puts "======================"
      expire_index
    end
  
    private
    def expire_index
      puts "======================"
      puts "   EXPIRING INDEX     "
      puts "======================"
      expire_action(:controller =&gt; '/posts', :action =&gt; 'index')
    end
  end
  </code></pre>
  
  <p><strong><code>config/environments/production.rb</code></strong></p>
  
  <pre><code>config.action_controller.perform_caching = true
  config.cache_store = :dalli_store # using memcachier on heroku
  </code></pre>