Add migration file handling
This is built on top of !2 (merged) and should be reviewed after the first one got in (or if you want to check it out before, I suggest to look on the second commit only).
Edited by Felix Delattre
This is built on top of !2 (merged) and should be reviewed after the first one got in (or if you want to check it out before, I suggest to look on the second commit only).