title: Rails, external url redirection issue
body: <p>when I use <code>redirect_to</code> this way:</p>
  
  <p><code>redirect_to "https://google.com</code></p>
  
  <p>There is no problem.
  But when I get the url from a method:</p>
  
  <pre><code>redirect_to external_url
  </code></pre>
  
  <p>.
  .
  .   </p>
  
  <pre><code>def external_url
    "https://google.com"
  end
  </code></pre>
  
  <p>I am getting this Error :</p>
  
  <pre><code> ERROR URI::InvalidURIError: URI must be ascii only "http://localhost:3000\u{202b}\u{202a}https://google.com"
  </code></pre>