Customize.md

+## Greenlight customization
+
 Customized version here in git in branch `fairteaching`.
 
 after doing changes do in `~/greenlight` or in `.env`
@@ -12,4 +14,17 @@ docker-compose up -d
 
 See http://docs.bigbluebutton.org/greenlight/gl-customize.html#restart-greenlight
 
-Language file: ~/greenlight/config/locales/de_DE.yml
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+Language file: ~/greenlight/config/locales/de_DE.yml
+
+## BBB modules customization
+
+after updates you might need to re-apply: 
+
+```
+cp ~/greenlight/config/bigbluebutton.properties /usr/share/bbb-web/WEB-INF/classes/bigbluebutton.properties 
+cp ~/greenlight/config/meteor_app_settings.yml /usr/share/meteor/bundle/programs/server/assets/app/config/settings.yml 
+cp ~/greenlight/config/turn-stun-servers.xml /usr/share/bbb-web/WEB-INF/classes/spring/turn-stun-servers.xml
+
+```
+
+(A script might do that job: https://docs.bigbluebutton.org/2.2/customize.html#automatically-apply-configuration-changes-on-restart)
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