Really digging this pattern for organizing different 'features' of a model.

Keeps related methods together and makes it easier to find relevant code as the codebase grows. Plus I can separate out test files by feature. Example: Tasks::DueDate

Tasks originally just had a due_date field. Eventually that grew to also support relative due dates ("10 days from start"). And we wanted a handful of helpers like `due_this_week?` and `overdue?`.

100 lines in a well-name module > 100 lines in the model