add loader in index public

public/index.html

@@ -13,7 +13,11 @@
     <noscript>
       <strong>We're sorry but <%= htmlWebpackPlugin.options.title %> doesn't work properly without JavaScript enabled. Please enable it to continue.</strong>
     </noscript>
-    <div id="app"></div>
+    <div id="app">
+      <div class="ui active dimmer">
+        <div class="ui indeterminate text loader">En cours de chargement ...</div>
+      </div>
+    </div>
     <!-- built files will be auto injected -->
   </body>
 </html>