add readme

web/script/py/readme.md

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+Run:
+
+# create a virtual env
+python3 -m venv venv 
+
+# activate the virtual env
+source venv/bin/activate
+
+# install dependencies into it
+pip install -r requirements.txt
+
+# sluggarize your local DB (idempotent; safe to run repeatedly)
+python3 sluggarize_jamtracks.py