Merge pull request #11989 from rtibbles/no_swappable_auth

Add pre-commit hook and documentation to prevent swappable model dependencies

.pre-commit-config.yaml

@@ -64,6 +64,11 @@ repos:
         kolibri/core/logger/migrations/0003_auto_20170531_1140\.py|
         kolibri/core/logger/migrations/0005_auto_20180514_1419\.py|
       )$
+  - id: no-swappable-auth-migrations
+    name: No migrations with swappable auth models (settings.AUTH_USER_MODEL)
+    entry: settings\.AUTH_USER_MODEL
+    language: pygrep
+    files: migrations/.*\.py$
 -   repo: https://github.com/isidentical/teyit
     rev: 0.4.3
     hooks:

docs/backend_architecture/upgrade.rst

@@ -20,6 +20,12 @@ that take a ``choices`` keyword argument, where the choices are strings. The
 strings should have no prefix (``u`` or ``b``) and the migration should contain
 ``from __future__ import unicode_literals`` as an import.
 
+For any migrations involving Foreign keys to the FacilityUser model, the migration
+will automatically be generated by Django to use a swappable dependency on settings.AUTH_USER_MODEL.
+This should be updated by removing the swappable dependency, setting a fixed migration dependency
+and replacing the reference to `settings.AUTH_USER_MODEL` with `"kolibriauth.FacilityUser"`
+instead. For an example of this, see this previous pull request: https://github.com/learningequality/kolibri/pull/11984 .
+
 We also use the upgrade functionality triggered during the CLI
 initialization to copy in new copies of static files that are used in the frontend
 app. These upgrades are only triggered for a subset of our CLI commands - start,