git介绍和讲解：https://www.liaoxuefeng.com/wiki/0013739516305929606dd18361248578c67b8067c8c017b000
错误“Please tell me who you are”的解决方法：
https://www.liaoxuefeng.com/discuss/001409195939432748a2c9fae3846bc98b3c2a547fa321b000/0014448919624489beb9bb3ae1f42408663e676952903e9000