如何在swift上刷新所有的firebase数据

How can I refresh all data on firebase on swift . What I'm trying to do is in another view controller my points are being updated when I return back to my main view controller where the points are displayed the points do not get updated until I close the app and open it again . So I was wondering if anyone knew a refresh function for firebase where I could refresh it on pull down or something like that How can I refresh all data on firebase on swift