删除提交记录,成为一个干净的仓库

1. Checkout

   git checkout --orphan latest_branch

2. Add all the files

   git add -A

3. Commit the changes

   git commit -am "commit message"

4. Delete the branch

   git branch -D master

5. Rename the current branch to master

   git branch -m master

6. Finally, force update your repository

   git push -f origin master