CHANGELOG.md in strong_json-0.8.0 vs CHANGELOG.md in strong_json-0.9.0

@@ -1,7 +1,11 @@
 # CHANGELOG
 
 ## master
 
+## 0.9.0 (2019-3-20)
+
+* [#12](https://github.com/soutaro/strong_json/pull/12): Fix type signature
+
 ## 0.8.0 (2018-10-29)
 
 * Add steep typechecking