renamed v2/models.rules to rule.py, updated comments

Author: calumbell

api_v2/models/rules.py renamed to api_v2/models/rule.py

@@ -4,15 +4,15 @@
 
 class RuleSet(HasName, HasDescription, FromDocument):
   """
-  The RuleGroup model contains a set of Rules as part of a larger article, or 
+  The RuleSet model contains a set of Rules as part of a larger article, or 
   as a chapter of a book.
   """
   key = key_field()
 
 
 class Rule(HasName, HasDescription, FromDocument):
   """"
-  The Rule model contains information about a single rule from a larger RuleGroup.
+  The Rule model contains information about a single rule from a larger RuleSet.
   Each Rule is typically a paragraph or two long and might contain tables.
   """