Added a new entry in the redirection_map

Author: javiereguiluz

redirection_map

@@ -13,6 +13,7 @@
 /cookbook/service_container/parentservices /components/dependency_injection/parentservices
 /cookbook/service_container/factories /components/dependency_injection/factories
 /cookbook/service_container/tags /components/dependency_injection/tags
+/cookbook/upgrading /cookbook/install/upgrading
 /reference/configuration/mongodb /bundles/DoctrineMongoDBBundle/config
 /reference/YAML /components/yaml
 /components/dependency_injection /components/dependency_injection/introduction