For people interested in this subject, you might also be interested in my project Reshape: https://github.com/fabianlindfors/reshape. It takes database migrations a step further than most tools, guaranteeing zero-downtime migration for both schema and data changes.
also separate question but I feel it would be nice to have a few "example" tutorials, where you go through setting a database with fake data, with a sample app which queries it in real-time in a different terminal and adds data or interact, and then going through a few updates / reverts, and be able to check that the sample app can still work perfectly without having to close it and restart, would be a quite useful "start tutorial" to get the idea of your lib
