Production database migration failing

[jlauinger]

A migration in #129 is not deployable on the production system: staff.0017_auto_20170202_2258

Migrating yields a

_mysql_exceptions.IntegrityError: (1452, 'Cannot add or update a child row: 
a foreign key constraint fails (`pyophase`.`#sql-30af_8ea73`, CONSTRAINT 
`staff_ophasecategory_id_3804b945_fk_ophasebase_ophasecategory_id` 
FOREIGN KEY (`ophasecategory_id`) REFERENCES `ophasebase_ophasecategory` (`id`))')

on the first run, and a

_mysql_exceptions.OperationalError: (1054, "Unknown column 
'groupcategory_id' in 'staff_settings_group_categories_enabled'")

in all further runs.

While investigating, I rolled back the database backup from today, Feb 7 03:02 CET. To revert the PR that introduced the incompatibility, revert c4c7a41:

git revert c4c7a411686ef951ee3730ca9b3b714c532534a4

[bhaettasch]

We should prioritize #77 to detect those issues in the future before merging.

[jlauinger]

To make pyophase deployable again (I needed a separate new feature), I reverted the original PR.

Further deployment and fixing the migration error should be done on the ophaseCategories branch. I opened a new PR #135 to discuss.

[bhaettasch]

Problem was resolved with merging #135, using the new migrations from 6e838ed