title: Deploying to heroku with git keeps getting rejected due to fast-forwards
body: <p>I keep getting the following fail with heroku + git...</p>
  
  <pre><code>$ heroku jammit:deploy --app XXXXXXXXXXX
  ===== Compiling assets...[OK]
  ===== Commiting assets...[OK]
  ===== Done...
  ===== Deploying assets for xxxxx-staging to heroku...
  To git@heroku.com:XXXXXXXX.git
   ! [rejected]        master -&gt; master (non-fast-forward)
  error: failed to push some refs to 'git@heroku.com:xxx-staging.git'
  To prevent you from losing history, non-fast-forward updates were rejected
  Merge the remote changes (e.g. 'git pull') before pushing again.  See the
  'Note about fast-forwards' section of 'git push --help' for details.
  [FAIL]
  ===== Done...
  ===== Deleting compiled assets...[OK]
  ===== Commiting deleted assets...[OK]
  ===== Done...
  $ git pull
  Already up-to-date.
  </code></pre>
  
  <p>Any ideas what I'm doing wrong or should be doing differently to allow for pushing without having to force a push?</p>
  
  <p>Thanks</p>