Enable rerere autoupdate
Enable rerere autoupdate

Without this setting when you have a conflict that is resolved by
rerere, the files would still be unstaged and marked as `UU` in `git
status`, so if you ran `git mergetool` it would fail saying no files
needed merging, but if you ran `git rebase --continue` it would fail
saying conflict needed to be resolved. This auto adds them so continuing
the rebase will be successful without having to do a `git add`

keith/dotfiles,keith/dotfiles,keith/dotfiles,keith/dotfiles,keith/dotfiles,keith/dotfiles