The problem Task Scheduler solves

It helps open-source contributors to keep track of the projects they are working on, tasks within them, their deadlines, etc.
It has a real-time database with authentication. Your friend sitting remotely can monitor your projects(obviously when you give him your email and password ;) and help you if needed. Apart from this common users can also use this app without any difficulty as it has a very simple and basic UI.
Hope it helps !!

Challenges I ran into

Resolved many bugs and added many cool features like swipe to delete, etc. UI still can be improved and animation effects can be added.