improve contributing.md

CONTRIBUTING.md

@@ -2,26 +2,41 @@
 
 Contributions are welcome as we aim to continue improving the pipeline. For instance, you can contribute by:
 
-- Reporting a bug
-- Reporting some difficulties in using the pipeline
+- Opening an issue
 - Discussing the current state of the code
-- Submitting a fix
-- Proposing new features
+- Making a Pull Request (PR)
 
-## Pull Requests
+If you want to open a PR, follow the following instructions.
 
-To add some new code to **sopa**, you should:
+## Installing `sopa` in editable mode
+
+When contributing, installing `sopa` in editable mode is recommended. Also, we recommend installing the 'dev' extra.
+
+For this, use one of the two following lines:
+
+```sh
+# with pip
+pip install -e '.[dev]'
 
-1. Install the dependencies.
-2. Create your personal branch from `dev`.
-3. Make sure you read the coding guidelines below.
-4. Implement your changes.
-5. Create a pull request on `dev` with explanations about your developed features. Then, wait for discussion and validation of your pull request.
+# or with poetry
+poetry install -E dev
+```
 
 ## Coding guidelines
 
 - Use the `black` formatter and `isort`. Their usage should be automatic as they are in the `pyproject.toml` file. Depending on your IDE, you can choose to format your code on save.
+- Run `flake8` inside the whole `sopa` directory, i.e. `flake8 sopa`
 - Follow the [PEP8](https://peps.python.org/pep-0008/) style guide.
 - Provide meaningful names to all your variables and functions.
 - Document your functions and type your function inputs/outputs.
-- Try as much as possible to follow the same coding style as the rest of the repository.
+- Try as much as possible to follow the same coding style as the rest of the repository.
+
+## Pull Requests
+
+To add some new code to **sopa**, you should:
+
+1. Fork the repository
+2. Install `sopa` in editable mode with the 'dev' extra (see above)
+3. Create your personal branch from `dev`
+4. Implement your changes
+5. Create a pull request on the `dev` branch. Add explanations about your developed features, and wait for discussion and validation of your pull request