Add contributing guidelines

CONTRIBUTING.md

@@ -0,0 +1,121 @@
+# Contributing to python-dispatch
+
+We love your input! We want to make contributing to this project as easy and transparent as possible, whether it's:
+
+- Reporting a bug
+- Discussing the current state of the code
+- Submitting a fix
+- Proposing new features
+
+## Pull Requests
+
+Pull requests are the best way to propose changes to the project. We actively welcome your pull requests.
+
+### Basic Steps
+
+1. Fork the [repo](https://github.com/nocarryr/python-dispatch) and **create a new
+    branch** from `master`.
+2. If you've added code that should be tested, add tests.
+3. If you've changed APIs, update the documentation.
+4. Ensure the test suite passes.
+5. Issue that pull request!
+
+### Your First Code Contribution
+
+Working on your first Pull Request? Here are a couple of resources to get you started:
+
+- [Github Help: Creating a pull request](https://help.github.com/en/desktop/contributing-to-projects/creating-a-pull-request)
+- [How to Contribute to an Open Source Project on GitHub](https://egghead.io/series/how-to-contribute-to-an-open-source-project-on-github)
+- [The FirstTimersOnly Movement](http://www.firsttimersonly.com/)
+
+
+## Limit Changes per Pull Request
+
+- Avoid changes to the project's configuration or meta-data such as
+  - Version Information
+  - Packaging Configuration
+  - Testing / Deployment Configuration
+- Try to avoid making large sets of changes if they could be broken into smaller ones.
+  Instead, split them into separate pull requests.
+
+## Coding Style
+
+While this project does not fully (probably not even partially) adhere to [PEP8](https://www.python.org/dev/peps/pep-0008/),
+the existing code-base does maintain a certain level of consistency.  Please try
+to follow the style if possible.  Don't worry about it too much though, there's no
+[flakes](https://pypi.org/project/pyflakes/) or [lint](https://www.pylint.org/) here.
+
+### Basic Guidelines
+
+- 4 spaces for indentation, not tabs.
+- Avoid trailing whitespace.
+- Prefer readability and clarity over complicated/complex: see the
+    [Zen of Python](https://www.python.org/dev/peps/pep-0020/)
+
+
+## Follow the Goals and Philosophy of the Project
+
+- No dependencies should ever be introduced.
+- Keep things simple and light-weight.
+- Avoid adding public methods/attributes to the `Dispatcher` class, especially
+  if the method/attribute names are common.
+  - Since `Dispatcher` is meant to be subclassed by users of this project,
+    it needs to stay out of a developer's way as much as possible.
+- Ensure compatibility across all conceivable platforms and Python versions. (currently 2.7, 3.4, 3.5, 3.6, 3.7)
+
+## Local Development
+
+### Environment / Installation
+
+```bash
+git clone https://github.com/<gh-user-name>/python-dispatch.git
+cd python-dispatch
+```
+
+It's recommended to use a virtual environment for development and testing.
+See https://virtualenv.pypa.io/en/latest/ or https://docs.python.org/3.7/library/venv.html for details.
+
+Create a new environment at the root of your working tree and activate it:
+```bash
+python -m venv venv
+source venv/bin/activate
+```
+
+Install the project in 'editable' mode:
+```bash
+pip install -e .
+```
+
+Currently, the only dependency for testing is [pytest](https://pypi.org/project/pytest/),
+but to make tests run faster, it's a good idea to install [pytest-xdist](https://pypi.org/project/pytest-xdist/):
+```bash
+pip install pytest pytest-xdist
+```
+
+### Running Tests
+
+To run the entire test suite:
+```bash
+py.test -n auto
+# -n auto will use all available CPU cores
+```
+
+For other invocation methods, see the [pytest docs](https://pytest.org/en/latest/)
+
+There is a test in the suite that will take an *extremely* long time: `tests/test_subclass_init.py`. To avoid having to wait for it every time, you can make
+a change to it, make sure to **revert it** before committing.
+
+`tests/test_subclass_init.py` line 83:
+```python
+for i in range(40000):          # <--- change this to something like 4000
+    before_init = time.time()
+```
+
+## License
+
+By contributing, you agree that your contributions will be licensed under
+project's (MIT) [license](LICENSE.txt).
+
+## References
+
+This document was adapted from the open-source contribution guidelines for [Facebook's Draft](https://github.com/facebook/draft-js/blob/a9316a723f9e918afde44dea68b5f9f39b7d9b00/CONTRIBUTING.md)

README.md

@@ -87,3 +87,15 @@ emitter.name = 'foo'
 emitter.value = 42
 # >>> emitter value is 42
 ```
+
+## Contributing
+
+Contributions are welcome!
+
+If you want to contribute through code or documentation, please see the
+[Contributing Guide](CONTRIBUTING) for information.
+
+## License
+
+This project is released under the MIT License. See the [LICENSE](LICENSE) file
+for more information.