All code should be seen/understood by more than one person

[Bjwebb]

Someone suggested this as a general approach to avoiding the loss of knowledge when a member of the team leaves.

This would involve someone extra checking all pull requests / newly commited code, even if the code if written by the "owner" of that repo.

I don't think we do this currently, but I think it's a good aspirational goal, and one that should hopefully become more achievable as the team grows.

We might want some sort of process in place for deciding who the second person should be, if it isn't the "owner".