Merge branch 'master' into guardian

# Conflicts:
#	Pipfile
#	Pipfile.lock
#	passbook/admin/views/invitations.py
#	passbook/admin/views/policy.py
#	passbook/admin/views/providers.py
#	passbook/admin/views/sources.py
#	passbook/admin/views/users.py

passbook/lib/tasks.py

@@ -0,0 +1,13 @@
+"""passbook misc tasks"""
+from django.core import management
+from structlog import get_logger
+
+from passbook.root.celery import CELERY_APP
+
+LOGGER = get_logger()
+
+@CELERY_APP.task()
+def backup_database():
+    """Backup database"""
+    management.call_command('dbbackup')
+    LOGGER.info('Successfully backed up database.')