我自己總結的規范：
feature: 功能添加
bugfix: bug修復
change: 調整，比如配置，某些方法替換等
optimize: 優化過程
doc: 文檔變更
refactor: 重構，功能不變
tests: 測試代碼的調整
merge：分支合並
delete：分支刪除
bugfix: ngx.ssl.session: avoided memory leaks when calling set_serialized_session repeatly. thanks spacewander for the patch.
optimize: corrected the initial table size of req socket objects. thanks spacewander for the patch.
doc: fixed a typo in a code comment. thanks Alex Zhang for the patch.
refactor: cleaned up some variable names and locals. thanks Thijs Schreijer for the patch.
tests: various changes in the test suite.
change: switched to SSL_version() calls from TLS1_get_version().
=================華麗的分割線==================
阮一峰的博客中推薦使用的git規范：http://www.ruanyifeng.com/blog/2016/01/commit_message_change_log.html
我自己用的話以自己的為准，阮一峰博客中的為輔。