add configuration lines to readme

README.md

@@ -42,11 +42,17 @@ To rebuild the frontend CSS styles (you need to do this at least once):
 
     gulp styles
 
+# Configuration
+
+see: config/config.json
+
 # Run
 
     export NODE_ENV=development
     npm start
 
+    open http://localhost:90000
+
 # License
 
 Spacedeck Open is released under the GNU Affero General Public License Version 3 (GNU AGPLv3).