Add documentation on developing echoSMs

.gitignore

@@ -2,4 +2,6 @@
 __pycache__/
 /dist
 /site
-/.ipynb_checkpoints
+/.ipynb_checkpoints
+echoSMs.code-workspace
+/.vscode

docs/developing.md

@@ -0,0 +1,43 @@
+# Developing echoSMs
+
+> These notes are a work in progress.
+
+This page contains notes and instructions on developing and adding new models to echoSMs.
+
+## Obtaining the source code
+
+The echoSMs [source code](https://github.com/ices-tools-dev/echoSMs) is kept on github under an [ICES](http://www.ices.dk/) account. Clone the repository with this URL:
+
+    https://github.com/ices-tools-dev/echoSMs.git
+
+
+
+## Generating packages for PyPI
+
+EchoSMs is a pure Python package. The build configuration is done via a [pyproject.toml](https://github.com/ices-tools-dev/echoSMs/blob/main/pyproject.toml) file and [`hatchling`](https://hatch.pypa.io/latest/) is used to produce packages.
+
+A github [action](https://github.com/ices-tools-dev/echoSMs/blob/main/.github/workflows/publish-to-pypi.yml) in the echoSMS repository will generate a Python wheel and source package and upload these to [PyPI](https://pypi.org/project/echosms/). This action is triggered whenever a tagged commit occurs to the repository. The tag is used as the new version number. EchoSMs version numbers follow the [semantic versioning](http://semver.org) convention.
+
+Every commit to the echoSMs repository will generate a development package being uploaded to [TestPyPI](https://test.pypi.org/project/echosms/#history). This is used to always check that a commit does not prevent production of a package and is where a package containing the latest commit can be obtained.
+
+## Documentation
+
+The echoSMs documentation is produced using [`mkdocs`](https://www.mkdocs.org/) and [`mkdocstring`](https://mkdocstrings.github.io/). The static documentation pages are hosted by github and are regenerated after every commit to the repository using a github [action](https://github.com/ices-tools-dev/echoSMs/actions/workflows/build-docs.yml).
+
+Documentation edits can be tested locally by running:
+
+    mkdocs serve
+
+in the top level of the echoSMs repository. The documentation is then available at <http://127.0.0.1:8000>.
+
+## Tests
+
+EchoSMs uses the pytest testing framework. After installing pytest, run the tests using
+
+    pytest -v
+
+in the top level of the echoSMs repository.
+
+## Adding a new scattering model
+
+TBD.

mkdocs.yml

@@ -5,6 +5,7 @@ nav:
     - Conventions: conventions.md
     - Benchmarks: benchmark_data.md
     - API reference: api_reference.md
+    - Developing echoSMs: developing.md
     - Other software: other_software.md
 
 theme: