diff --git a/Design:-Version-Control.md b/Design:-Version-Control.md
index 4d22484..e3028c0 100644
--- a/Design:-Version-Control.md
+++ b/Design:-Version-Control.md
@@ -36,6 +36,8 @@ The existing API has separate methods for saving flows and credentials. The new
 ### `Storage.init(runtime)`
  - `runtime` : a RED runtime object
 
+Returns a promise that resolves when the storage subsystem has been initialised and is ready for subsequent API requests.
+
 Passing in the runtime object allows the storage mechanism to access the `settings`, `log` components properly as well as `comms` if it needs to send notifications to the user.
 
 ### `Storage.getFlows([id])`