for a real database that works like git, see http://www.datomic.com
if git killed svn, datomic kills postgres
if it were open source maybe, but i'm definitely not going to switch (even though i might want to) for licensing reasons. in fact, i have more motivation to write an libre datomic clone than to pay cognitect anything for their proprietary db.
do it!
Depending on the definition of "it", someone has: https://github.com/tonsky/datascript