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.

Review the repository's existing slide structure and the Appendix in the training manual before creating the slide. Done means a new slide, including another octocat, has been added from scratch and fits the manual.

索引モデルが issue の本文から書いたものです。