Fix undefined settings in k8s scripts

In k8s, creating a user is an interactive command, so it needs to run in
exec. Thus, the DJANGO_SETTINGS_MODULE needs to be defined for this
command.

Close #344

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 Note: Breaking changes between versions are indicated by "💥".
 
+## Unreleased
+
+- [Bugfix] Fix undefined settings in k8s scripts, such as `createuser`
+
 ## v10.0.7 (2020-06-22)
 
 - [Bugfix] Fix TypeError on viewing xblock

tutor/scripts.py

@@ -3,6 +3,7 @@ from . import fmt
 from . import plugins
 
 BASE_OPENEDX_COMMAND = """
+export DJANGO_SETTINGS_MODULE=$SERVICE_VARIANT.envs.$SETTINGS
 echo "Loading settings $DJANGO_SETTINGS_MODULE"
 """