title: relationships one to many with coredata
body: <p>I am a newbie Swift developer and I am creating an app for myself where you can capture the time you spend doing a certain activity (so basically it involves a timer). I want this app to track your progress daily thus I have an calendar and a pie chart to show the info. This app is using core data and I am struggling with how to use core data to track the daily progress of the certain activity. So basically how to use relationships with core data. If you know any good sources(or courses) for learning core data feel free to leave them down below, it will help me a lot.</p>