add object assign polyfill

dashboard-ui/legacy/objectassign.js

@@ -0,0 +1,23 @@
+if (typeof Object.assign != 'function') {
+    (function () {
+        Object.assign = function (target) {
+            'use strict';
+            if (target === undefined || target === null) {
+                throw new TypeError('Cannot convert undefined or null to object');
+            }
+
+            var output = Object(target);
+            for (var index = 1; index < arguments.length; index++) {
+                var source = arguments[index];
+                if (source !== undefined && source !== null) {
+                    for (var nextKey in source) {
+                        if (source.hasOwnProperty(nextKey)) {
+                            output[nextKey] = source[nextKey];
+                        }
+                    }
+                }
+            }
+            return output;
+        };
+    })();
+}