Alternate backend support for config files

I'm working on a release management web app to manage branching and picking of commits onto release branches and push those changes back out to other services. Because multiple nodes in the app need to have a unified view of the repository I'm experimenting with non-filesystem storage technologies (specifically Postgres and Amazon's DynamoDB) for the workload. So far the Ref and Object DB backend support has worked exactly as expected but support for alternate config storage is missing. I notice there is backend support for configs in libgit2 similar to the Ref and Object DBs and am happy to start implementing support for this feature in Rugged. This issue is more to solicit feedback and start a discussion before I dig into adding this feature.

Start by comparing Rugged's existing Ref and Object DB backend support with the config backend support available in libgit2. Determine the entry points and interfaces involved before proposing support for Postgres or DynamoDB. Done means alternate config storage works consistently for the unified repository view and has appropriate coverage.