add docstrings

internal/data/IIdentifiable.go

@@ -1,6 +1,7 @@
 package data
 
-// TODO docstring
+// Defines an Id function that uniquely identifies an object. This may be used
+// as a primary key in a database/ datastore. 
 type IIdentifiable interface {
     Id() string // not allowed to contain a ':'
 }