adding todo

Author: geospatial-jeff

README.md

@@ -64,3 +64,4 @@ Once deployed, end-users may subscribe to the newly created SNS topic to be noti
 # TODOS
 - Add support for dynamic catalogs ([sat-api](https://github.com/sat-utils/sat-api), [staccato](https://github.com/boundlessgeo/staccato)).
 - Add aggregator service for metrics/logging etc on batch jobs.
+- Add SNS event source.