Merge branch 'database-abstraction' into 'master'

.gitignore

management/forms.py

management/management/commands/create_admin.py

management/templates/management/add_election.html

management/templates/management/election.html

management/views.py

requirements_dev.txt

vote/forms.py

vote/migrations/0028_auto_20210804_2335.py

...rations/0029_rename_unpublished_and_disable_abstention.py

vote/models.py

vote/selectors.py

vote/templates/vote/index_election_item.html

vote/templates/vote/spectator_election_item.html

vote/templates/vote/vote.html

vote/tests.py

vote/urls.py

vote/views.py