docs: add CONTRIBUTING.md (#304)

* initial draft of CONTRIBUTING.md

* make changes suggested in review

Co-Authored-By: Yusuke Wada <yusuke@kamawada.com>

* fix the styles

---------

Co-authored-by: Yusuke Wada <yusuke@kamawada.com>

Author: sahithyandev

CONTRIBUTING.md

@@ -0,0 +1,86 @@
+# Contributing to HonoX
+
+This document outlines guidelines for contributing to HonoX. Please take a moment to review it before submitting your contributions.
+
+## How Can I Contribute?
+
+### Reporting Bugs
+
+If you find a bug, please open an issue on our [GitHub Issues](https://github.com/honojs/honox/issues) page.
+
+When reporting a bug, please include:
+
+- A clear and concise description of the bug.
+- Steps to reproduce the behavior.
+- Expected behavior.
+- Screenshots or GIFs if applicable.
+- Your environment details (OS, dependency versions, etc.).
+
+### Suggesting Enhancements
+
+Got an idea for a new feature or improvement? We'd love to hear it! Please open an issue on our [GitHub Issues](https://github.com/honojs/honox/issues) page.
+
+When suggesting an enhancement, please include:
+
+- A clear and concise description of the enhancement.
+- Why you think it would be valuable to the project.
+- Any potential alternatives or considerations.
+
+### Pull Request Guidelines
+
+1. Fork the repository and create your branch from `main`.
+2. Make your changes.
+3. Ensure your code adheres to our style guides (see [Style guides](#style-guides)).
+4. Write clear, concise commit messages (see [Git Commit Messages](#git-commit-messages)).
+5. Test your changes thoroughly.
+6. Update documentation if your changes require it.
+7. Open a pull request to the `main` branch.
+
+In your pull request, please:
+
+- Reference the issue you are addressing (e.g., `Fixes #123`).
+- Provide a clear summary of your changes.
+- Include any relevant screenshots or GIFs.
+
+## Development Setup
+
+To get started with development, follow these steps:
+
+Clone the repository:
+
+```bash
+git clone https://github.com/[your-username]/honox.git
+cd honox
+```
+
+Install dependencies:
+
+```bash
+bun install
+```
+
+We are using bun and strongly recommend it.
+
+## Style guides
+
+### Git Commit Messages
+
+We follow the [Conventional Commits](https://www.conventionalcommits.org/en/v1.0.0/) specification for our commit messages. This helps us generate consistent and readable commit histories.
+
+Examples:
+
+- `feat: Add new user authentication`
+- `fix: Correct typo in README`
+- `docs: Update installation guide`
+- `refactor: Improve error handling logic`
+
+### Code Style
+
+We use [Eslint](https://eslint.org/) and [Prettier](https://prettier.io/) for code formatting. Please ensure your code is formatted correctly before submitting a pull request.
+
+You can lint and format your code using:
+
+```bash
+bun run lint:fix
+bun run format:fix
+```