Import from <http://motememo.g.hatena.ne.jp/keyword/%E3%82%84%E3%82%8B%E5%A4%AB%E3%81%A7%E5%AD%A6%E3%81%B6%20gitcore-tutorial>

for some deep reasons *.g.hatena.ne.jp/keyword/* is not
    Google-reachable. heh.