title: Capistrano error tar: This does not look like a tar archive
body: <pre><code> INFO [050fe961] Running mkdir -p /home/rails/rails-
  capistrano/releases/20140114234157 on staging-rails
  DEBUG [050fe961] Command: cd /home/rails/rails-capistrano/repo &amp;&amp; ( PATH=/opt/ruby/bin:$PATH GIT_ASKPASS=/bin/echo GIT_SSH=/tmp/rails/git-ssh.sh mkdir -p /home/rails/rails-capistrano/releases/20140114234157 )
   INFO [050fe961] Finished in 0.142 seconds with exit status 0 (successful).
   INFO [2dea2fe5] Running git archive feature/Capistrano | tar -x -C /home/rails/rails-capistrano/releases/20140114234157 on staging-rails
  DEBUG [2dea2fe5] Command: cd /home/rails/rails-capistrano/repo &amp;&amp; ( PATH=/opt/ruby/bin:$PATH GIT_ASKPASS=/bin/echo GIT_SSH=/tmp/rails/git-ssh.sh git archive feature/Capistrano | tar -x -C /home/rails/rails-capistrano/releases/20140114234157 )
  DEBUG [2dea2fe5]    fatal: Not a valid object name
  DEBUG [2dea2fe5]    tar: This does not look like a tar archive
  DEBUG [2dea2fe5]    tar: 
  DEBUG [2dea2fe5]    Exiting with failure status due to previous errors      
  </code></pre>
  
  <p>I am confused about two things:</p>
  
  <ol>
  <li><p>Why is Capistrano running <code>git archive</code> here:<br>
  <code>git archive feature/Capistrano | tar -x -C /home/rails/rails-capistrano/releases/20140114234157</code></p></li>
  <li><p>Why is <code>tar</code> failing?</p></li>
  </ol>