diff --git a/js/shift.js b/js/shift.js
index a1ffe87..f39e555 100644
--- a/js/shift.js
+++ b/js/shift.js
@@ -311,4 +311,7 @@ Shift.thaw = function (jsonShift) {
     shift.id = jsonShift.id;
     shift.Dauer = moment.duration(jsonShift._duration);
     return shift;
-};
\ No newline at end of file
+};
+Shift.prototype.updateBeginn = function(hour) {
+    this._begin = this._begin.add('hours', hour);
+}