old_contents: import DS from 'ember-data';
  
  var SiteSerializer = DS.RESTSerializer.extend({
    serialize: function(site, options) {
      var fields = [ 'name', 'tagline', 'description', 'moreDesc', 'joinText' ];
      var result = { };
  
      fields.forEach(function(field) {
        result[field] = site.get(field);
      });
  
      if (options && options.includeId) {
        result['id'] = site.get('id');
      }
  
      return result;
    }
  });
  
  export default SiteSerializer;
  
new_contents: import DS from 'ember-data';
  
  var SITE_SERIALIZER_FIELDS = [ 'name', 'tagline', 'description', 'moreDesc', 'joinText' ];
  
  var SiteSerializer = DS.RESTSerializer.extend({
    serialize: function(site, options) {
      var result = site.getProperties(SITE_SERIALIZER_FIELDS);
  
      if (options && options.includeId) {
        result['id'] = site.get('id');
      }
  
      return result;
    }
  });
  
  export default SiteSerializer;
  
subject: Use more idiomatic ember api