Adding coc to header

Author: jhill1

_includes/header.html

@@ -4,8 +4,9 @@ <h1><a href="{{ site.baseurl }}/" class="site-title" >{{ site.title }}</a></h1>
     <nav id="nav">
         <ul>
             <li><a href="{{ site.baseurl }}/">Home</a></li>
+	    <li><a href="{{ site.baseurl }}/coc.html">Code of Conduct</a></li>
             <li><a href="{{ site.baseurl }}/people/index.html">People</a></li>
-	         <li><a href="{{ site.baseurl }}/publications">Publications</a></li>
+	    <li><a href="{{ site.baseurl }}/publications">Publications</a></li>
         </ul>
     </nav>
 </header>