Update contributors: fix typo

Author: nvella

index.html

@@ -72,7 +72,7 @@ <h3><a id="authors-and-contributors" class="anchor" href="#authors-and-contribut
     <li><a href="http://blogs.msdn.com/b/mthree/">M3 Sweatt</a></li>
     <li><a href="https://github.com/martinwoodward">Martin Woodward</a></li>
     <li><a href="http://michaelcummings.net/">Michael Cummings</a></li>
-    <li><a href="https://github.com/nvella_">Nick Vella</a></li>
+    <li><a href="https://github.com/nvella">Nick Vella</a></li>
     <li><a href="http://blog.robdolin.com/">Rob Dolin</a></li>
     <li><a href="https://github.com/RobStand">Robert Standefer</a></li>
     <li><a href="https://github.com/rginn">Robin Ginn</a></li>