update settings to allow mongo host and remove unused health check

userid

services/notifications/config/settings.defaults.coffee

@@ -5,10 +5,4 @@ module.exports = Settings =
 			host: process.env["LISTEN_ADDRESS"] or "localhost"
 
 	mongo:
-		url : "mongodb://#{process.env["MONGO_HOST"] or "localhost"}/sharelatex"
-
-	notifications:
-		healthCheck:
-			user_id: "5620bece05509b0a7a3cbc62"
-
-
+		url: process.env['MONGO_CONNECTION_STRING'] or "mongodb://#{process.env["MONGO_HOST"] or "localhost"}/sharelatex"