update the demo server section of the developer doc
update the demo server section of the developer doc

indirectlylit/kolibri,mrpau/kolibri,indirectlylit/kolibri,lyw07/kolibri,lyw07/kolibri,lyw07/kolibri,mrpau/kolibri,indirectlylit/kolibri,learningequality/kolibri,indirectlylit/kolibri,mrpau/kolibri,learningequality/kolibri,learningequality/kolibri,lyw07/kolibri,learningequality/kolibri,mrpau/kolibri