Add README.md to project folder

Author: dalito

template/project/README.md.jinja

@@ -0,0 +1,9 @@
+# Code generated from the linkML model
+
+This directory holds the output generated with [LinkML generators](https://linkml.io/linkml/generators/index.html)
+from the model in `src/{{project_slug}}/datamodel/schema/{{project_slug}}.yaml`.
+Generators transform a linkml schema into another datamodel such as SQL or RDF, or into other artefacts,
+such as JSON-Schema, a visualisation, or markdown documentation.
+
+In a future version of the template this directory will be empty except for the readme.
+Thereby updating the template will never interfere with code that you generated from your model.