Replace ID of My Classroom link to my-classroom

This is to get the exercise in "Working with Browser Events" > "The Default Action" to work if students decide to use the code from GitHub instead of their workspace.

Author: jaycode

Diff for: index.html

@@ -157,7 +157,7 @@
             data-analytics-payload="{"cta_message":"Blog","cta_type":"link","cta_destination":"new_window","cta_location":"HomePage"}"
             class="button button--navigation button--student button--blog" href="http://blog.udacity.com/"
             style="display: inline;">Blog</a>
-          <a id="ga-99cff7" title="My Classroom" data-show-student="" data-analytics-name="Navbar Link Clicked"
+          <a id="my-classroom" title="My Classroom" data-show-student="" data-analytics-name="Navbar Link Clicked"
             data-analytics-category="Navbar Link" data-analytics-label="Navbar Link - Classroom - My Classroom"
             data-analytics-payload="{&quot;cta_message&quot;:&quot;My Classroom&quot;,&quot;cta_type&quot;:&quot;button&quot;,&quot;cta_destination&quot;:&quot;self&quot;,&quot;cta_location&quot;:&quot;HomePage&quot;}"
             class="button button--primary button--student" href="https://classroom.udacity.com/"
@@ -1397,4 +1397,4 @@ <h3>
   <script src="app.js"></script>
 </body>
 
-</html>
+</html>