[Chinese] Case Study: Design 12306 + code deployment system

in this video, we talked about the design of 12306: https://docs.google.com/document/d/1SxnY_qXui7OClJxgCYzAa2cXVIAseRPUOlhrccughGU/edit and a code deployment system: https://docs.google.com/document/d/1X0WBrqalFCCtc3U_pGWnsLPpSIfGvswXY-4U7ekGLb4/edit