Update README.md

Mention BabyBuddy

README.md

@@ -17,3 +17,6 @@ The app will be developed with react-native and typescript. Database will likely
 Circalog sleep diary format specification, intended to be generic to store a maximum of pertinent data for any kind of circadian periodic event, is readable here: https://github.com/Circadiaware/circalog/blob/main/docs/circalog-format-spec.md
 
 An [interactive mock-up app](https://design.penpot.app/#/view/441c1550-c424-11eb-8557-f55ab9adbb41?page-id=d0e73e20-e124-11eb-a77a-195c36c76d76&index=0&share-id=1bc0a800-1ba4-11ec-9c71-4a8af25a7bed) is available on Penpot (the screenshot above is of this mock-up app). Please use Chrome based browsers preferably, as there may be [an issue](https://github.com/penpot/penpot/issues/1081) with Firefox based browser which makes the text not display correctly, although the mock-up was modified to workaround this issue. On mobiles, the default view may be too small, click on the fullscreen button at the top right corner in the Penpot interface to show the app in almost real size. Backup files for the Penpot project are available in the docs folder.
+
+Similar projects:
+* [BabyBuddy](https://github.com/babybuddy/babybuddy), opensource webapp with a native [Android app](https://github.com/babybuddy/babybuddy-for-android) with multiple time trackers, very interesting implementation very similar to circalog, but can only specify what the timer was about at the end, not at the start. Also, graphs and stats are very limited since the goal is not to track sleep disorders.