0. 先去Sourcetree官网下载最新的软件，然后翻墙注册下（注册很简单的）
1. 在控制台输入命令 ssh-keygen -t rsa -C "你的email地址" 生成rsa
Generating public/private rsa key pair.
Enter file in which to save the key (/Users/sunww/.ssh/id_rsa): id_rsa
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in id_rsa.
Your public key has been saved in id_rsa.pub.
The key fingerprint is:
SHA256:Hfmn1iZ1m+sew4fa+70kEitokYzmMsvzx4hZ
The key's randomart image is:
+---[RSA 2048]----+
+----[SHA256]-----+
2.将上面生成的id_rsa.pub文件的秘匙内容（control + A）全部拷贝到我的gitlab设置下面的 SSH Keys中然后ok，随便输入一个title，然后ok
3.给本地的sourcetree添加秘匙
命令 ssh-add /Users/sunww/id_rsa
TF012778:~ sunww$ ssh-add /Users/sunww/id_rsa
Enter passphrase for /Users/sunww/id_rsa:
Identity added: /Users/sunww/id_rsa (/Users/sunww/id_rsa)
4. 然后打开sourcetree，新建url
通过以上几步的配置处理，你就可以enjoy your code ！