Persisting Commits

[joepio]

Commits are atomic changes to a resource. If these are persisted, we can use these to generate logs and previous versions. Pretty cool.

I think it makes sense to simply store these as resources (since they are just that) - not as some special struct.

One thing I'm still pondering about, is how to deal with failed commits. For now, if a commit cannot be applied, it will not be stored. This works fine for synchronous APIs (e.g. posting a Commit to a /commit endpoint), but this would not work when these commits are sent in bulk.

• Make Commit convertible to Resource (requires nested resources Storing & querying nested resources #16)
• Persist them when a delta is successfully applied (in store.commit())

For the future:

• Generate commits when importing atomic data (parsing ad3, for example)
• Limit write access to the commit API (maybe)
• Start thinking about how to generate older versions of resources, and how to query these resources (probably TPF)