Cache commit's author and committer when indexing a commit

... as these data are not cached in rugged. It makes some difference for repos with large number of commits.

LGTM, could you also add a changelog item?

Thanks for the looking into this gem. It needs some love.

Added 1 commit:

• 1146ec48 - Update CHANGELOG

Done.

Status changed to merged

Mentioned in commit 4015a896

$ gem push gitlab-elasticsearch-git-1.0.2.gem
Pushing gem to https://rubygems.org...
Successfully registered gem: gitlab-elasticsearch-git (1.0.2)

Excellent. Thanks, Valery.