[README] add order by to roadmap 0.3
@@ -162,8 +162,8 @@ $ make test
## Roadmap
- [x] 0.1 support aggregation select
-- [ ] 0.2 support distributed query
-- [ ] 0.3 support group by
+- [ ] 0.2 support distributed query (WIP)
+- [ ] 0.3 support group by, order by
- [ ] 0.4 support join
- [ ] 0.5 support sub queries
- [ ] 0.6 support TPC-H benchmark
