Fix backup restore

This merge request fixes the backup restore system.

Note that it might not be backward compatible.

Fixes #492

beat/web/experiments/models/result.py

@@ -73,6 +73,7 @@ class Result(models.Model):
             self.name,
             self.cache.hash,
         )
+    natural_key.dependencies = ['experiments.cachedfile']
 
 
     def value(self):