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.

Inspect the repository for existing slide files and compare their structure before choosing where the new slide belongs. Create one additional slide featuring an octocat, following the established format; the issue provides no named file or test to run, so completion is confirmed by reviewing the rendered or source slide set.

索引モデルが issue の本文から書いたものです。