Retro-benchmark new repositories

[art-w]

When a new project is added to current-bench, it starts with no previous history and so provide no immediate value. We could add a way to rewind the git history to prefill the graphs with interesting metrics (and demonstrate that the CB integration works!)

This is a bit tricky because the make bench target will not exist in the past! We need a way of knowing which commits should be rebased in the past.

• The commits that add current-bench integration could be made available on a current-bench branch? Then we know what to rebase.
• The current-bench branch could also be useful for "testing" out CB without polluting the default branch graphs? How does the user then trigger the activation of the rollback on the main branch?
• We can stop the git replay on rebase conflict, and with a max of 20 commits (no need to replay too far in the past!)

[punchagan]

#87 seems related. Just tagging here so we can close the other issue, when we work on this, or even supersede that one right away.

[art-w]

Oh you're right, I missed #87 in my survey and created a duplicate!