title: Base-level rules cannot contain the parent-selector-referencing character '&'
body: <p>I'm flowing the ROR 4 tutorials , There is a chapter mentioned about Compiling Sass to CSS . I modified (<code>#logo:hover and #footer:hover</code>)  to  <code>&amp; :hover</code>  But error occurred</p>
  
  <pre><code>Base-level rules cannot contain the parent-selector-referencing character '&amp;'.
   (in/Users/snailwalker/rails_projects/sample_app/app/assets/stylesheets/custom.css.scss:54)
  </code></pre>
  
  <p>My SCSS:</p>
  
  <pre><code>/* header */
  #logo {
    float: left;
    margin-right: 10px;
    font-size: 1.7em;
    color: #fff;
    text-transform: uppercase;
    letter-spacing: -1px;
    padding-top: 9px;
    font-weight: bold;
    line-height: 1;
  }
  &amp; :hover {
    color: #fff;
    text-decoration: none;
  }
  </code></pre>