Update CONTRIBUTING.md to enhance development guidelines (#824)

Same as line/line-bot-sdk-php#715

Author: eucyt

CONTRIBUTING.md

@@ -1,16 +1,76 @@
-## How to contribute to LINE Bot SDK for Python project
+# How to contribute to LINE Bot SDK for Python project
 
-First of all, thank you so much for taking your time to contribute! LINE Bot SDK for Python is not very different from any other open
-source projects you are aware of. It will be amazing if you could help us by doing any of the following:
+First of all, thank you so much for taking your time to contribute!
+LINE Bot SDK for Python is not very different from any other open source projects you are aware of.
+It will be amazing if you could help us by doing any of the following:
 
-- File an issue in [the issue tracker](https://github.com/line/line-bot-sdk-python/issues) to report bugs and propose new features and
-  improvements.
-- Ask a question using [the issue tracker](https://github.com/line/line-bot-sdk-python/issues).
+- File an issue in [the issue tracker](https://github.com/line/line-bot-sdk-python/issues) to report bugs and propose new features and improvements.
+- Ask a question using [the issue tracker](https://github.com/line/line-bot-sdk-python/issues) (__Please ask only about this SDK__).
 - Contribute your work by sending [a pull request](https://github.com/line/line-bot-sdk-python/pulls).
 
-### Contributor license agreement
+## Development
+
+### Install dependencies
+
+Run `pip install -r requirements-dev.txt` to install all dependencies for development and testing.
+
+### Understand the project structure
+
+The project structure is as follows:
+
+- `linebot`: The main library code.
+- `tests`: Test code.
+- `examples`: Example projects that use the library.
+- `generator`: Custom OpenAPI generator for Python code.
+- `tools`: Development tools.
+- `docs`: Documentation files for Sphinx.
+
+### Edit OpenAPI templates
+
+Most of the API client code is generated with OpenAPI Generator based on [line-openapi](https://github.com/line/line-openapi)'s YAML files.
+You cannot edit almost all code under `linebot/v3/` directly.
+
+If you need to change the generated code, you should modify the custom templates under:
+- `generator/src/main/resources/python-nextgen-custom-client/`
+
+After editing the templates, run `python generate-code.py` to regenerate the code, and then commit all affected files.
+If not, CI status will fail.
+
+When you update code, be sure to check consistencies between generated code and your changes.
+
+### Add unit tests
+
+We use [pytest](https://pytest.org/) for unit tests.
+Please add tests to the appropriate test directories to verify your changes.
+
+Especially for bug fixes, please follow this flow for testing and development:
+1. Write a test before making changes to the library and confirm that the test fails.
+2. Modify the code of the library.
+3. Run the test again and confirm that it passes thanks to your changes.
+
+### Run your code in your local environment
+
+You can use the [example projects](examples/) to test your changes locally before submitting a pull request.
+
+### Run CI tasks in your local environment
+
+Test by using tox.
+To run all tests and to run flake8 against all versions, use: `tox`
+
+To run all tests against version 3.10, use: `tox -e py3.10`
+
+To run a test against version 3.10 and against a specific file, use: `tox -e py3.10 -- tests/test_webhook.py`
+
+### Documentation
+
+If you edit README.rst, you should execute the following command to check the syntax of README.
+
+```
+python -m readme_renderer README.rst
+```
+
+## Contributor license agreement
 
 When you are sending a pull request and it's a non-trivial change beyond fixing typos, please make sure to sign
 [the ICLA (individual contributor license agreement)](https://cla-assistant.io/line/line-bot-sdk-python). Please
 [contact us](mailto:dl_oss_dev@linecorp.com) if you need the CCLA (corporate contributor license agreement).
-

README.rst

@@ -376,63 +376,6 @@ Contributing
 ------------
 Please check `CONTRIBUTING <CONTRIBUTING.md>`__ before making a contribution.
 
-For SDK developers
-------------------
-
-First install for development.
-
-::
-
-    $ pip install -r requirements-dev.txt
-
-
-You can generate new or fixed models and APIs by this command.
-
-::
-
-    $ python generate-code.py
-
-
-When you update line-bot-sdk-python version, please update `linebot/__about__.py <linebot/__about__.py>`__ and generate code again.
-
-
-If you edit `README.rst <README.rst>`__, you should execute the following command to check the syntax of README.
-
-::
-
-    $ python -m readme_renderer README.rst
-
-
-Run tests
-~~~~~~~~~
-
-Test by using tox. We test against the following versions.
-
--  3.9
--  3.10
--  3.11
--  3.12
--  3.13
-
-To run all tests and to run ``flake8`` against all versions, use:
-
-::
-
-    tox
-
-To run all tests against version 3.10, use:
-
-::
-
-    $ tox -e py3.10
-
-To run a test against version 3.10 and against a specific file, use:
-
-::
-
-    $ tox -e py3.10 -- tests/test_webhook.py
-
-
 .. |PyPI version| image:: https://badge.fury.io/py/line-bot-sdk.svg
    :target: https://badge.fury.io/py/line-bot-sdk