App Badge - remaining cards due

Option to show an app badge (red number on mobile app icon) that indicates how many outstanding cards are currently unfinished. This idea is implemented by another study app (that one is focused on learning to read Japanese) which is open source for iOS so perhaps there is some useful inspiration on their repo: https://github.com/davidsansome/tsurukame

I love having this with the Tsurukame app as an easy reminder to study my remaining cards for the day. If I see a red badge on the app I know I should get to work and immediately know how many cards are left to get down to 0 for the day.