Write a detailed summary at the bottom of the spec/plan document of what was done, how, and why, and files worked on during the implementation.
The structure should look like this:
EXAMPLE of a single phase implementation summary:
Phase 1 Implementation Summary (Completed)
What was done
How it was done
Why it was done|
Files worked on
EXAMPLE of a multi phase implementation summary:
Phase 1-4 Implementation Summary (Completed)
What was done
How it was done
Why it was done
Files worked on