update IDEAS.md, as nested collections & histograms are done
update IDEAS.md, as nested collections & histograms are done

Change-Id: Ibc68d07575e1e9f010696ea884c2d2b8cf379ebd
Reviewed-on: http://review.couchbase.org/77838
Well-Formed: Build Bot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>
Reviewed-by: Steve Yen <ef850f73f7832052d3c6d9b5ddd3a1716d9a57f1@gmail.com>
Tested-by: Steve Yen <ef850f73f7832052d3c6d9b5ddd3a1716d9a57f1@gmail.com>

steveyen/moss,steveyen/moss,couchbaselabs/moss