Add more things to TODO
# TODO
-## 2019.12.05
+## 2019.12.21
### Primary
### Subs
+- [ ] Implement `WithJSON` for `DataFrame`
+ - [x] `to_json_value`
+ - [ ] `from_json_value`
- [ ] Implement various pdf
- [x] Bernoulli
- [x] Beta
