add documentation file, outsourced from usage

Author: brainelectronics

docs/DOCUMENTATION.md

@@ -0,0 +1,40 @@
+# Documentation
+
+Documentation is generated by using Sphinx and published on RTD
+
+---------------
+
+## Documentation
+
+Documentation is automatically created on each merge to the development
+branch, as well as with each pull request and available
+[:books: here at Read the Docs][ref-rtd-micropython-modbus]
+
+### Install required packages
+
+```bash
+# create and activate virtual environment
+python3 -m venv .venv
+source .venv/bin/activate
+
+# install and upgrade required packages
+pip install -U -r docs/requirements.txt
+```
+
+### Create documentation
+
+Some usefull checks have been disabled in the `docs/conf.py` file. Please
+check the documentation build output locally before opening a PR.
+
+```bash
+# perform link checks
+sphinx-build docs/ docs/build/linkcheck -d docs/build/docs_doctree/ --color -blinkcheck -j auto -W
+
+# create documentation
+sphinx-build docs/ docs/build/html/ -d docs/build/docs_doctree/ --color -bhtml -j auto -W
+```
+
+The created documentation can be found at [`docs/build/html`](docs/build/html).
+
+<!-- Links -->
+[ref-rtd-micropython-modbus]: https://micropython-modbus.readthedocs.io/en/latest/