title: rbenv not showing the available ruby versions
body: <p>I have installed <code>rbenv</code> in my vagrant machine but when I try to list all the available ruby versions <code>rbenv versions</code> then it gives me this output:</p>
  
  <p><code>system (set by /home/vagrant/.rbenv/version)</code></p>
  
  <p>Does anyone know what is this?</p>