roschaefer a86b26a756 Various fixes for data migrations
* Add unique index for `Migration`s
* Fix proper use of `next` callback. First argument is potential error.
* Update migration template
2020-01-20 17:25:36 +01:00
..
2020-01-20 17:25:36 +01:00
2020-01-20 17:25:36 +01:00