Fix formatting for new entry.

Author: lapets

index.html

@@ -217,6 +217,7 @@ <h2>Spring 2019 Course Offering</h2>
             <br/>Computer Science 504: <a href="https://lapets.io/course/504-2019-spr/">Data Mechanics</a>
           </b>
         </div>
+        <br/>
         <div class="section">
           <a id="2018spring"></a>
           <h2>Spring 2018 Course Offering</h2>