docs: update readme for structures pruning scripts

scripts/structures_pruning/README.md

@@ -0,0 +1,46 @@
+# Structures Pruning Scripts
+
+This directory contains the MongoDB structures pruning script that was
+migrated from the [tubular](https://github.com/openedx/tubular)
+repository.
+
+This can be useful to keep the MongoDB `modulestore.structures`
+collection size in check. This script could be called from any
+automation/CD framework.
+
+# Quick start
+
+> [!NOTE]
+> See [How to Use the Structures Pruning Script](https://docs.openedx.org/en/latest/site_ops/how-tos/use-the-structures-pruning-script.html) for a complete guide to running this in production.
+
+Some quick steps for setting this up to run. A shallow clone of
+openedx-platform is recommended because the repository is very large.
+
+```bash
+git clone --depth=1 https://github.com/openedx/openedx-platform.git
+cd openedx-platform
+virtualenv venv
+source venv/bin/activate
+pip install -r ./scripts/structures_pruning/requirements/base.txt
+```
+
+Then you can use python to run the scripts, and view the integrated
+help.
+
+```bash
+python scripts/structures_pruning/structures.py --help
+```
+
+# Development
+
+For development, you can also install the testing requirements:
+
+```bash
+pip install -r scripts/structures_pruning/requirements/testing.txt
+```
+
+Run the test cases using pytest:
+
+```bash
+pytest scripts/structures_pruning
+```