--- a/app/views/tweets/show.atom.erb	Thu Jul 28 03:49:08 2016 +0900
+++ b/app/views/tweets/show.atom.erb	Thu Jul 28 03:56:56 2016 +0900
@@ -1,21 +1,16 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <feed xml:lang="en-US" xmlns="http://www.w3.org/2005/Atom">
-  <id>
-    tag:<%= request.host_with_port %>,2005:<%= @user.id %>
-  </id>
+  <id><%= atom_id(@user.id) %></id>
 
   <link rel="alternate" type="text/html" href="<%= request.protocol %><%= request.host_with_port %>" />
   <link rel="self" type="application/atom+xml" href="<%= request.url %>" />
 
-  <title>
-    <%= @user.name %> (<%= @user.screen_name %>)
-  </title>
-  <icon>
-    <%= @user.profile_image_url_https %>
-  </icon>
+  <title><%= "#{@user.name} (#{@user.screen_name})" %></title>
+  <icon><%= @user.profile_image_url_https %></icon>
+
   <updated>
     <%= @tweets.first.try(:created_at) || Time.at(0) %>
   </updated>
 
-  <%= render(:partial => "tweet", :collection => @tweets, :cached => ->(f) { f.id }) %>
+  <%= render :partial => "tweet", :collection => @tweets, :cached => ->(f) { f.id } %>
 </feed>