For starters, we can just maintain a repo and commit these decisions/events to it.
I guess, then, the question is:
1. Is this really needed ? 2. If go ahead with this approach, what are those events or decisions worth committing?
some examples from the top of my head:
* we decided to rewrite the auth flow. why? => ...
* we chose language xyz for this particular module...
We obviously have a wiki that has concrete things like setting up your laptop, information about existing products, blah blah.