DVC backend

[wlandau]

Prework

• Read and agree to the Contributor Code of Conduct and contributing guidelines.
• If there is already a relevant issue, whether open or closed, comment on the existing thread instead of posting a new issue.
• New features take time and effort to create, and they take even more effort to maintain. So if the purpose of the feature is to resolve a struggle you are encountering personally, please consider first posting a "trouble" or "other" issue so we can discuss your use case and search for existing solutions first.
• Format your code according to the tidyverse style guide.

Proposal

• https://dvc.org
• Could build some gittargets wrapper functions on top of https://github.com/andrewcstewart/dvc-r.

[wlandau]

Related:

• Don't overwrite former results when target is modified, like in drake targets#641
• Data versioning idea targets#686
• Mege two targets directories? targets#255
• best practices for distributing metadata/cached results? targets#509
• Thoughts on data storage locations other than _targets targets#297
• Best practice to compare the results before and after code change targets#305

cc @liutiming

[wlandau]

Tabling. With ropensci/targets#711, I am not sure this will be necessary.