Get List of Items
function (query, next) {
        switch (ctx.type) {
          case 'model':
            Model.find(query, next);
            break;
          case 'relation':
            Model.findOne(query, function (err, instance) {
              if (err) return next(err);
              var builder = new _queryBuilder2.default({
                type: ctx.type,
                count: ctx.count,
                now: ctx.now,
                nowISOString: ctx.nowISOString,
                params: {
                  range: ctx.params.range,
                  where: ctx.params.where,
                  custom: ctx.params.custom
                }
              });
              builder.onComplete(function (_err, _query) {
                if (_err) return next(_err);
                instance[ctx.relation || ctx.params.relation](_query, next);
              });
              builder.build();
            });
            break;
          case 'nested':
            Model.findOne(query, function (err, instance) {
              return next(err, instance[ctx.nested]);
            });
            break;
          default:
            next(null, []);
        }
      }