Merge branch 'backend-tests' into 'master'

.gitlab-ci.yml

backend/.coveragerc

backend/.gitignore

backend/core/migrations/0001_initial.py

backend/core/migrations/0003_student_matrikel_no.py

backend/core/models.py

backend/core/permissions.py

backend/core/serializers.py

backend/core/tests/__init__.py

backend/core/tests/data_factories.py

backend/core/tests/test_access_rights.py

backend/core/tests/test_auth.py

backend/core/tests/test_examlist.py

backend/core/tests/test_student_page.py

backend/core/tests/test_tutor_api_endpoints.py

backend/core/tests/tests.py

backend/core/urls.py

backend/core/views.py

backend/delbert.py

backend/grady/settings/default.py