Implement a manifest builder, to allow for easier management of state around constructing manifests

data/model/image.py

@@ -366,6 +366,13 @@ def get_image(repo, docker_image_id):
     return None
 
 
+def get_image_by_db_id(id):
+  try:
+    return Image.get(id=id)
+  except Image.DoesNotExist:
+    return None
+
+
 def synthesize_v1_image(repo, image_storage_id, storage_image_size, docker_image_id,
                         created_date_str, comment, command, v1_json_metadata, parent_image=None):
   """ Find an existing image with this docker image id, and if none exists, write one with the