@mdarveau and @dsgermain raise up a good point in #9 about versioning. While we've said that we would version the spec in the repository via git tags, we did not actually ever decide where to indicate the GBFS version in the feed.

I can imagine two logical places for this:

1. In gbfs.json, in which case we would want to make this file required (though the version field would be the only file that was required - the auto-discovery mechanism would change to optional)
2. In system_information.json, but this doesn't really make sense since it's metadata about the feed, not about the system

I am leaning toward including it in gbfs.json but would like other people's thoughts.