update snippet for second test page

Author: djih

test/browser/amplitudejs2.html

@@ -16,7 +16,7 @@
           this._q.push([fn].concat(Array.prototype.slice.call(arguments, 0))); return this;
         };
       }
-      var identifyFuncs = ['add', 'set', 'setOnce', 'unset'];
+      var identifyFuncs = ['add', 'append', 'set', 'setOnce', 'unset'];
       for (var i = 0; i < identifyFuncs.length; i++) {
         proxyIdentify(identifyFuncs[i]);
       }