title: Rails Friendly_Id on Heroku, Heroku not updating slugs
body: <p>I've set up the <a href="https://github.com/norman/friendly_id/" rel="nofollow">friendly_id</a> gem, following along to the <a href="http://railscasts.com/episodes/314-pretty-urls-with-friendlyid" rel="nofollow">RailsCasts Screencast</a> on it. Locally this works brilliantly, I installed it, ran through <code>User.find_each(&amp;:save)</code> which successfully updated the slug field on each of the existing users and all was fine.</p>
  
  <p>I have now pushed this to Heroku, and although it works fine for any new members that are added, Heroku isn't updating the user slug for me for already existing Users.</p>
  
  <p>Running <code>heroku run console</code> and then <code>User.find_each(&amp;:save)</code> just does nothing:</p>
  
  <pre><code>irb(main):001:0&gt; User.find_each(&amp;:save)
    User Load (20.2ms)  SELECT "users".* FROM "users" WHERE ("users"."id" &gt;= 0) ORDER BY "users"."id" ASC LIMIT 1000
      (23.6ms)  BEGIN
      (2.0ms)  COMMIT
      (13.6ms)  BEGIN
      (21.1ms)  COMMIT
  =&gt; nil
  </code></pre>
  
  <p>The relevant code in <code>models/user.rb</code> is:</p>
  
  <pre><code>extend FriendlyId
  friendly_id :name, use: :slugged
  def should_generate_new_friendly_id?
    new_record?
  end
  </code></pre>
  
  <p>And I've run all DB migrations on Heroku and they went fine. I checked and the <code>users</code> table does have a <code>slug</code> field, but it's empty and I'm not sure where I'm going wrong here. If anyone happens to have come across this before, any advice would be much appreciated. Thank you.</p>