Update changelog to describe the Step-by-Step porting guide

Step-By-Step porting sample suikan4github#12
suikan4github#12

CHANGELOG.md

@@ -2,11 +2,21 @@
 Record of the modification in project development.
 
 ## [Unreleased]
-- [Issue 5 : HAL_GPIO_EXTI_Callback() needs to avoid the null pointer access](https://github.com/suikan4github/murasaki/issues/5)
+
+### Added
 - [Issue 6 : Add CubeMX configuration note to the porting guide.](https://github.com/suikan4github/murasaki/issues/6)
+- [Issue 10 : Write an install script](https://github.com/suikan4github/murasaki/issues/10)
+- [Issue 12 : Step-By-Step porting sample](https://github.com/suikan4github/murasaki/issues/12)
+
+### Changed
+- [Issue 5 : HAL_GPIO_EXTI_Callback() needs to avoid the null pointer access](https://github.com/suikan4github/murasaki/issues/5)
 - [Issue 7 : README.md doesn't have link to the "where to get" at ToC](https://github.com/suikan4github/murasaki/issues/7)
 - [Issue 8 : ADD link to murasaki_samples to README.md](https://github.com/suikan4github/murasaki/issues/8)
-- [Issue 10 : Write an install script](https://github.com/suikan4github/murasaki/issues/10)
+
+### Deprecated
+### Removed
+### Fixed
+### Security
 
 ## [0.1.0] - 2019-02-11