feat: add AirShelf core implementation

core/backend/airshelf/settings/test.py

@@ -0,0 +1,13 @@
+from .base import *  # noqa: F403
+
+
+DEBUG = False
+DATABASES = {
+    "default": {
+        "ENGINE": "django.db.backends.sqlite3",
+        "NAME": ":memory:",
+    }
+}
+PASSWORD_HASHERS = ["django.contrib.auth.hashers.MD5PasswordHasher"]
+CELERY_TASK_ALWAYS_EAGER = True
+CELERY_TASK_EAGER_PROPAGATES = True