title: Using $ sudo bundle exec ... raises 'bundle: command not found' error
body: <p>I have installed rbenv on an Ubuntu sever. I can cd into my application directory and run <code>$ bundle</code> without issue, however I need to run <code>$ sudo bundle exec ...</code> and this gets me an error: </p>
  
  <blockquote>
    <p>bundle: command not found</p>
  </blockquote>
  
  <p>Why is this and how can I fix it?</p>