morphlib: add artifact cache reference class

The artifact cache doesn't need to know the whole of an artifact object
to be able to retrieve something from the cache, just the basename.

This can be generated from the contents, or just saved itself.

1 files changed, 1 insertions, 0 deletions

diff --git a/morphlib/__init__.py b/morphlib/__init__.py
index baf4c253..4d9ad22e 100644
--- a/morphlib/__init__.py
+++ b/morphlib/__init__.py
@@ -26,6 +26,7 @@ class Error(cliapp.AppException):
 
 
 import artifact
+import artifactcachereference
 import artifactresolver
 import bins
 import buildenvironment