Customize.md

@@ -20,6 +20,11 @@ See http://docs.bigbluebutton.org/greenlight/gl-customize.html#restart-greenligh
 
 Language file: ~/greenlight/config/locales/de_DE.yml
 
+after updating greenlight from upstream: 
+
+1. `ruby bin/bundle update`    
+2. Gemfile.lock öffnen und letzten 2 Zeilen löschen (Bundle Version)
+
 ## BBB modules customization
 
 we keep a copy of config files of modules which are outside greenlight in its config directory, as this is in git: