Merge branch '56-don-t-store-notebook-output-cells' into 'master'

Resolve "Don't store notebook output cells"

Closes #56

See merge request sis/courses/machinelearning-introduction-workshop!41

.hooks/pre-commit

+#!/bin/sh
+
+for U in "$(git diff --cached --name-only)"; do
+    # skip files staged for deletion
+    test -e "$U" || continue
+    if [[ "$U" =~ .ipynb$ ]]; then
+        jupyter nbconvert --debug --ClearOutputPreprocessor.enabled=True --inplace "$U"
+    fi
+    git add "$U"
+done

CONTRIBUTING.md

+# Contributing
+
+Install Python version matching one specified in `binder/runtime.txt`.
+
+Setup development environment:
+
+    $ python -m venv .venv
+    $ source .venv/bin/activate
+    $ pip install -U pip setuptools
+    $ pip install -r binder/requirements.txt
+    $ ./binder/postBuild
+
+Register Git hooks (auto-remove output cells on commit):
+
+    $ git config core.hooksPath .hooks
+
+Launch JupyterLab:
+
+    $ jupyter lab
+
+Edit (improve) notebooks.

binder/postBuild

@@ -13,4 +13,4 @@ jupyter serverextension enable --py jupyter_lsp  --sys-prefix
 npm cache clean --force
 
 mkdir -p  ~/.jupyter/lab/user-settings/@jupyterlab/notebook-extension/
-echo '{"codeCellConfig": {"lineNumbers": true}, "recordTiming": true}' > ~/.jupyter/lab/user-settings/@jupyterlab/notebook-extension/tracker.jupyterlab-settings
+echo '{"codeCellConfig": {"lineNumbers": true}, "recordTiming": false}' > ~/.jupyter/lab/user-settings/@jupyterlab/notebook-extension/tracker.jupyterlab-settings

binder/requirements.txt

 black
 isort
+jupyter_contrib_nbextensions
 jupyterlab
 jupyterlab-code-formatter
 jupyterlab-execute-time