added migrations for instant delivery

node_modules/react-router/lib/behaviors/ImitateBrowserBehavior.js

@@ -0,0 +1,29 @@
+'use strict';
+
+var LocationActions = require('../actions/LocationActions');
+
+/**
+ * A scroll behavior that attempts to imitate the default behavior
+ * of modern browsers.
+ */
+var ImitateBrowserBehavior = {
+
+  updateScrollPosition: function updateScrollPosition(position, actionType) {
+    switch (actionType) {
+      case LocationActions.PUSH:
+      case LocationActions.REPLACE:
+        window.scrollTo(0, 0);
+        break;
+      case LocationActions.POP:
+        if (position) {
+          window.scrollTo(position.x, position.y);
+        } else {
+          window.scrollTo(0, 0);
+        }
+        break;
+    }
+  }
+
+};
+
+module.exports = ImitateBrowserBehavior;