应用场景：
我们在自己的私有测试分支上调试项目逻辑，给文件做了一些特定的修改，但是文件不想被git提交，不想执行git status命令时出现在modified列表里；再比如，我们本地的数据库和测试环境的数据库配置是不一样的，但是在项目开发中每次提交过程中忽略数据库配置文件。那么你这里就可以把不想提交的文件忽略。
当然关于git忽略文件的方式有很多，我这里使用的是git update-index --assume-unchanged命令。
代码举例：
Administrator@USER-20180915BE MINGW64 /e/数梦工场/uniapp/alipay-miniprogram (fsy-branch)
$ git status //执行git status 命令,私有分支修改过两个文件
On branch fsy-branch
Your branch is up to date with 'origin/fsy-branch'.
Changes not staged for commit:
(use "git add <file>..." to update what will be committed)
(use "git restore <file>..." to discard changes in working directory)
modified: common/api.js
modified: pagesU/liquorLicense/liquorLicense.vue
no changes added to commit (use "git add" and/or "git commit -a")
//执行忽略命令，注意文件的路径，否则会报错
Administrator@USER-20180915BE MINGW64 /e/数梦工场/uniapp/alipay-miniprogram (fsy-branch)
$ git update-index --assume-unchanged common/api.js //忽略api.js文件
Administrator@USER-20180915BE MINGW64 /e/数梦工场/uniapp/alipay-miniprogram (fsy-branch)
$ git status //验证文件是否被忽略
On branch fsy-branch
Your branch is up to date with 'origin/fsy-branch'.
Changes not staged for commit:
(use "git add <file>..." to update what will be committed)
(use "git restore <file>..." to discard changes in working directory)
modified: pagesU/liquorLicense/liquorLicense.vue //验证成功，api.js成功被忽略
no changes added to commit (use "git add" and/or "git commit -a")
Administrator@USER-20180915BE MINGW64 /e/数梦工场/uniapp/alipay-miniprogram (fsy-branch)
$ git update-index --no-assume-unchanged common/api.js //恢复跟踪
Administrator@USER-20180915BE MINGW64 /e/数梦工场/uniapp/alipay-miniprogram (fsy-branch)
$ git status //再次验证
On branch fsy-branch
Your branch is up to date with 'origin/fsy-branch'.
Changes not staged for commit:
(use "git add <file>..." to update what will be committed)
(use "git restore <file>..." to discard changes in working directory)
modified: common/api.js //恢复成功
modified: pagesU/liquorLicense/liquorLicense.vue
no changes added to commit (use "git add" and/or "git commit -a")
