add development guide (#1739)

CONTRIBUTING.md

@@ -0,0 +1,47 @@
+## Testing Changes
+
+1. Activate the ComfyUI environment.
+
+2. Build package locally after making changes.
+
+```bash
+# from inside the ComfyUI-Manager directory, with the ComfyUI environment activated
+python -m build
+```
+
+3. Install the package locally in the ComfyUI environment.
+
+```bash
+# Uninstall existing package
+pip uninstall comfyui-manager
+
+# Install the locale package
+pip install dist/comfyui-manager-*.whl
+```
+
+4. Start ComfyUI.
+
+```bash
+# after navigating to the ComfyUI directory
+python main.py
+```
+
+## Manually Publish Test Version to PyPi
+
+1. Set the `PYPI_TOKEN` environment variable in env file.
+
+2. If manually publishing, you likely want to use a release candidate version, so set the version in [pyproject.toml](pyproject.toml) to something like `0.0.1rc1`.
+
+3. Build the package.
+
+```bash
+python -m build
+```
+
+4. Upload the package to PyPi.
+
+```bash
+python -m twine upload dist/* --username __token__ --password $PYPI_TOKEN
+```
+
+5. View at https://pypi.org/project/comfyui-manager/