Add notes in readme

Author: rly

README.md

@@ -2,6 +2,14 @@
 
 Support for N-dimensional arrays in LinkML.
 
+# Quick reference for common commands
+
+```bash
+cd linkml-model
+poetry run gen-json-schema tests/input/examples/schema_definition-array-2.yaml
+poetry run gen-pydantic tests/input/examples/schema_definition-array-2.yaml
+```
+
 # Acknowledgements
 
 This [cookiecutter](https://cookiecutter.readthedocs.io/en/stable/README.html) project was developed from the [monarch-project-template](https://github.com/monarch-initiative/monarch-project-template) template and will be kept up-to-date using [cruft](https://cruft.github.io/cruft/).