Remove legacy multi-tenant support

Multi-tenenacy schould not live in one database.

• Turn School object into a real singleton object (using the best choice of the Django singleton modules)
• Remove SchoolRelated
• Update parent classes and unique constraints for all models in all apps and update migrations
• Make all parts that rely on the .school relation to use the School singleton

We can add multi-tenancy again in the future using one of the existing frameworks that use PostgreSQL schemas.

assigned to @nik

added part::backend label

mentioned in issue #77 (closed)

created branch 115-remove-legacy-multi-tenant-support to address this issue

marked the checklist item Remove SchoolRelated as completed

changed the description

mentioned in commit 0e377b4f

marked the checklist item Update parent classes and unique constraints for all models in all apps and update migrations as completed

marked the checklist item Make all parts that rely on the .school relation to use the School singleton as completed

@debdolph, can you please create the migrations for all apps for this?

Done

Thanks, but nothing changed in the repository and no migrations appeared anywhere. Created the one for BiscuIT-ng now.

I created the one for Chronos in biscuit-merge.

created merge request !64 (merged) to address this issue

mentioned in merge request !64 (merged)

marked the checklist item Create migrations as completed