Update documentation to reflect recent changes

README.md

@@ -15,6 +15,7 @@ but a brief overview of the components:
 * `sheetsync` syncs specifc database columns to a google doc which is the primary operator interface.
 * `thrimshim` acts as an interface between the `thrimbletrimmer` editor and the database.
 * `thrimbletrimmer` is a browser based video editor.
+* `segment_coverage` regularly checks whether there is complete segment coverage for each hour. 
 * `database` hosts a Postgres database to store events to be edited.
 * `nginx` provides a webserver through which the other components are exposed to the outside world.
 * `common` provides code shared between the other components.