add loading gif

js/controller.js

@@ -19,8 +19,11 @@ class Controller {
 
   cloneRep(repurl) {
     var that = this;
+    var loading = document.getElementsByClassName("loading")[0];
+    loading.style.display = "grid";
     this.model.cloneRep().then(
       function (value) {
+        loading.style.removeProperty("display");
         that.redrawDirTree(that.view);
       },
       function (error) {}