Can you confirm for me that the JSON type is easily indexable? [Seems like it is](http://stackoverflow.com/questions/17807030/how-to-create-index-on-json-field-in-postgres-9-3) but it would be good to know for sure before committing to it ([vs. hstore](http://www.craigkerstiens.com/2013/07/03/hstore-vs-json/)).