Minor: add Relationship::toString().

Author: aseemk

lib/Node._coffee

@@ -24,7 +24,8 @@ module.exports = class Node extends PropertyContainer
         super db, data
 
     #
-    # Return a string representation of this node.
+    # Return a human-readable string representation of this node,
+    # suitable for development purposes (e.g. debugging).
     #
     # @return {String}
     #

lib/Relationship._coffee

@@ -57,6 +57,17 @@ module.exports = class Relationship extends PropertyContainer
 
     ### Methods: ###
 
+    #
+    # Return a human-readable string representation of this relationship,
+    # suitable for development purposes (e.g. debugging).
+    #
+    # @return {String}
+    #
+    toString: ->
+        # this library has no notion of unsaved relationships,
+        # so assume this relationship has an id:
+        "relationship @#{@id} (#{@type})"
+
     #
     # Persist or update this relationship in the database. "Returns" (via
     # callback) this same instance after the save.