Improve the README

## Do you have a favorite Git Resource?
Add it to the README!
If you need help, check out the Appendix in the training manual.

Open the repository README and review the Appendix in the training manual if you need context. Add a favorite Git resource to the README; the work is done when the resource appears there in a useful, readable form.

由索引模型根据 Issue 内容生成。