Add a migration to load users and buckets

migrations/004_load_seed_file.py

@@ -0,0 +1,24 @@
+"""
+Load initial user and bucket data from seed files.
+"""
+import logging
+import os
+import subprocess
+import sys
+
+log = logging.getLogger(__name__)
+
+
+def up(db):
+    names = db.collection_names()
+
+    if "users" in names:
+        log.info("users collection already created")
+        return
+
+    if "buckets" in names:
+        log.info("buckets collection already created")
+        return
+
+    invoke = os.path.join(os.path.dirname(sys.executable), "invoke")
+    subprocess.call([invoke, "load_seed"])