Add A New Slide

## We Need More Slides
Grab another octocat and create a new slide from scratch.
If you need help, check out the Appendix in the training manual.

No file or test is named in the issue. Review the repository's existing slide structure and the Appendix in the training manual first, then create a new slide from scratch featuring another octocat; done means the added slide is present in the project.

索引モデルが issue の本文から書いたものです。