Merge pull request #190 from vespa-engine/tgm/doc-exchange-data

Update documentation: exchange data with applications page

Author: Thiago G. Martins

docs/sphinx/source/howto.rst

@@ -6,7 +6,7 @@ How-to guides
 
    howto/create_app_package/create_app_package
    howto/deploy_app_package/deploy_app_package
-   howto/exchange_data_with_app/exchange_data_with_app
+   howto/exchange_data_with_app/exchange-data-with-app
    query-model
    query
    evaluation