Freeze the time in tests.

Fixes remaining issues in Percy.

Author: CvX

ember-cli-build.js

@@ -49,5 +49,11 @@ module.exports = function(defaults) {
     // modules that you would like to import into your application
     // please specify an object with the list of modules as keys
     // along with the exports of each module as its value.
+    app.import('node_modules/timekeeper/lib/timekeeper.js', {
+        using: [
+            { transformation: 'cjs', as: 'timekeeper' },
+        ],
+    });
+
     return app.toTree();
 };