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CONTRIBUTING.md

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+# Contributing to this Package
+
+That you're reading this must mean you consider contributing to
+this package. So first off: Awesome! 👍🤘
+
+## Bugs
+
+In case you encounter any bugs please
+[file an issue](https://github.com/crwlrsoft/robots-txt/issues/new).
+Describe the issue as well as you can and provide an example to
+reproduce it.  
+Maybe you're not 100 percent sure whether what you've discovered
+is a bug or the intended behavior. You can still file an issue
+and tell us which results you'd expect.
+
+If you know how to fix the issue you're welcome to send a pull
+request. 💪
+
+## New Features
+
+If you have ideas for new features you can tell us about it on
+[Twitter](https://twitter.com/crwlrsoft) or via
+[crwlr.software](https://www.crwlr.software/contact) or just
+send a pull request. Please keep in mind that there is no
+guarantee that your feature will be merged.
+
+## Conventions
+
+### Coding Style
+
+This package follows the
+[PSR-12](https://www.php-fig.org/psr/psr-12/) coding standard.
+Linting can be executed using the `composer cs` command.
+
+### Branching
+
+The repo contains branches for every minor version and a master
+branch up to date with the latest tagged version. For a bugfix
+please send your pull request to the branch of the latest version
+affected by the issue. If you're developing a new feature, branch
+out from the master branch.
+
+### CI
+
+When you're making changes to this package please always run
+unit tests, CS Fixer and PHPStan. Commands:  
+`composer test`  
+`composer cs`
+`composer stan`
+
+Ideally you add the pre-commit git hook that is shipped with
+this repo that will run tests and linting. Add it to your local
+clone by running:  
+`composer add-git-hooks`
+
+Also please don't forget to add new test cases if necessary.
+
+### Documentation
+
+For any code change please don't forget to add an entry to the
+`CHANGELOG.md` file and in case it's necessary also change the
+`README.md` file.
+
+## Appreciation
+
+When your pull request is merged I will show some love and tweet
+about it. Also if you meet me in person I will be glad to buy you
+a beer.