title: Cant figure out why my SASS wont work
body: <p>Hey I am trying to learn rails and following the rails tutorial. I am adding some elements to the apps style sheets using SCSS and this is what I am adding</p>
  
  <pre><code>/* miscellaneous */
  
    .debug_dump {
      clear: both;
      float: left;
      width: 100%;
      margin-top: 45px;
      @include box_sizing;
    }
  }
  </code></pre>
  
  <p>but when I go to view my it in a browser I receive this error</p>
  
  <pre><code>Mixin box-sizing is missing argument $boxmodel.
    (in /Users/&lt;mynamehere&gt;/workspace/sample_app/app/assets/stylesheets/custom.css.scss:110)
  
  &lt;html&gt;
      &lt;head&gt;
        &lt;title&gt;&lt;%= full_title(yield(:title)) %&gt;&lt;/title&gt;
        &lt;%= stylesheet_link_tag "application", media: "all",
                                               "data-turbolinks-track" =&gt; true %&gt;
        &lt;%= javascript_include_tag "application", "data-turbolinks-track" =&gt; true %&gt;
        &lt;%= csrf_meta_tags %&gt;
  
   Rails.root: /Users/&lt;mynamehere&gt;/workspace/sample_app
  </code></pre>
  
  <p>Any help would be much appreciated. Here is a link to my <a href="https://github.com/claytonnewberry/sample_app" rel="nofollow">github</a> if you need to see anything else</p>