Updated Design: Persistable Context (markdown)

Design:-Persistable-Context.md

@@ -149,3 +149,23 @@ flow.get("foo.bar"); // return 1
 > HU: Persistable Context do not support this.  
 >     If there are some problems, we will consider how solve those.
 >> DCJ - Agreed for version 1. 
+
+* key name of default storage
+
+In the case that `file` is not declared but `default` is declared on contextStorage, if a context data is specified like `$file.count`, Node-RED stores the key name in the default storage.
+In this case, there are two options for storing the key name.
+1. `$file.count` (The whole name that a user specified)
+
+Pros: Name confliction can be avoided.
+
+Cons: The rule will become complicated especially when a user directly accesses to the context data (e.g. on redis).
+
+2. `count` (The key name without storage name)
+
+Pros: Store a key name in the same rule of the other context storage.
+
+Cons: If a user uses a same key name for the different storages, name confliction will occur.
+
+My proposal is as follows. Do you agree with this option?
+  - Choose the option 2.
+  - Encourage a unique key name by writing it on design note.