https://blog.wongcw.com/2019/03/02/%e6%90%b6%e5%85%88uber%e4%b8%80%e6%ad%a5lyft%e6%9c%80%e5%bf%ab%e9%80%b1%e5%85%ad%e6%8f%90%e4%ba%a4ipo%e6%8b%9b%e8%82%a1%e6%9b%b8/