@hisakonog for the update of schema of our models between versions, i used the backbone parse function (it is autmoatically called when we fetch and build data from the server). this was tricky because it was already being overridden by backbone couchdb, so the trick was to save the original parse function in backbone couchdb as `originalParse : Backbone.Model.prototype.parse,` so that we can call it inside the custom parse function after we are done cleaning up the models. i did this for both datum and corpus...