Adding an example Jupyter notebook

First off: thank you for considering a contribution to diffeqzoo’s examples. The more examples we have, the better! Here is how to add a notebook.

1. Create the .ipynb file in docs/source/example_notebooks and fill it with content

2. Sync the notebook to a markdown file via jupytext. Check out these instructions. This is useful to keep the git diff clean and legible.

3. Make sure the example dependencies in setup.cfg are sufficient. We try to keep the optional dependencies small, but are not as strict with the example dependencies as with the remaining ones.

4. Add the notebook to docs/source/index.rst. If you skip this step, the notebook will not be rendered in the docs.

5. Add the .ipynb file to the .gitignore and to the clean job in the makefile. Do this after syncing it to a markdown version.

6. Check that everything passes the quality checks via make format example doc lint.

7. Make a pull request with your changes.