application.js

import DS from "ember-data";
import ENV from "devon-discovery/config/environment";

var ApplicationAdapter = DS.ActiveModelAdapter.extend({
  namespace: ENV.api.namespace,
  headers: {
    'Accept': 'application/json',
  },
  serializePolymorphicType: function(record, json, relationship) {
    var key = relationship.key;
    var belongsTo = Ember.get(record, key);
    var jsonKey = Ember.String.underscore(key + "_type");

    if (Ember.isNone(belongsTo)) {
      json[jsonKey] = null;
    } else {
      json[jsonKey] = capitalize(camelize(belongsTo.constructor.typeKey));
    }
  }
});

export default ApplicationAdapter;