title: how get the exact public path where a rails app lives
body: <p>Lets assume my RoR app lives at </p>
  
  <blockquote>
    <p><a href="http://case-1.example.com/part-1/sub-part-1/" rel="nofollow">http://case-1.example.com/part-1/sub-part-1/</a></p>
  </blockquote>
  
  <p>In a view file, how can I get that path?</p>