Added button to upgrade mangaDownloader via website

templates/index.html

@@ -10,8 +10,9 @@
       <div class="header">Super Awesome Mange Downloading and Maybe Someday Viewing Thing</div>
       <div class="nav" align="left">
         <ul>
-          <li><button class=button onclick="activeReturn()">Active</button>
-          <li><button class=button onclick="downloadReturn()">Download</button>
+            <li><button class=button onclick="activeReturn()">Active</button></li>
+            <li><button class=button onclick="downloadReturn()">Download</button></li>
+          <li><button class=button onclick="upgrade()">Update</button></li>
          <!-- <li><a href="http://google.com"><button class=button>google<>/button></a></li>
           <li><button class=button onclick="clickTest()">asdfl</button></li>-->
         </ul>
@@ -28,6 +29,11 @@
 <script>
   var manga = '';
 
+  function upgrade() {
+      fetch('/upgrade', {
+          method: 'PUT'
+      })
+  }
   function activeReturn() {
       document.getElementById('main').innerHTML= '';