#1113 Link uml-reverse-mapper created class diagrams to readme, where needed

data-mapper/README.md

@@ -12,6 +12,7 @@ tags:
 ## Intent
 A layer of mappers that moves data between objects and a database while keeping them independent of each other and the mapper itself
 
+## Class diagram
 ![alt text](./etc/data-mapper.png "Data Mapper")
 
 ## Applicability