I went to GitHub トレーニングチームから学ぶ Git の内部構造 @京都 : ATND last Tuesday. There I rememberd that when I first began to use Git (2008 or so), I read gitcore-tutorial, which lead me to know Git itself deeper. But my knowledge has been stopping at the time. The GitHub class shoed me to the up-to-date Git internals. Reading gitcore-tutorial, I was writing "やる夫で学ぶ gitcore-tutorial" (Study gitcore-tutorial with