Flexible end #541

[the-moog]

tox passes, no errors

[llazzaro]

Hi!
I'm not merging this PR yet since the GitHub pipeline needs to test migrations against different databases.
There was multiple issues with MySQL in the past and adding a migration is not so easy to the project.
Once I add the check against different databases I will merge this one.

Thanks for the contribution!

[coveralls]

Coverage: 79.89% (-0.1%) from 79.986% when pulling f795b59 on the-moog:flexible-end-#541 into 8aa6f87 on llazzaro:develop.