working date in json for stats

stats.py

 from server import *
 import json
+from jobs import date_json_handler
 
 @app.route('/stats')
 @register_navbar('Statistiken', icon='stats')
@@ -20,4 +21,4 @@ def stats_data(dataname, parameter=None):
 		data = query(statsqueries[dataname],parameter)
 	else:
 		data = query(statsqueries[dataname])
-	return Response(json.dumps(data),  mimetype='application/json')
+	return Response(json.dumps(data, default=date_json_handler),  mimetype='application/json')