Add CONTRIBUTING.md

CONTRIBUTING.md

@@ -0,0 +1,132 @@
+# Contributing to Atree
+
+The following is a set of guidelines for contributing to Atree.
+These are mostly guidelines, not rules.
+Use your best judgment, and feel free to propose changes to this document in a pull request.
+
+## Table Of Contents
+
+[Getting Started](#project-overview)
+
+[How Can I Contribute?](#how-can-i-contribute)
+
+- [Reporting Bugs](#reporting-bugs)
+- [Suggesting Enhancements](#suggesting-enhancements)
+- [Your First Code Contribution](#your-first-code-contribution)
+- [Pull Requests](#pull-requests)
+
+[Styleguides](#styleguides)
+
+- [Git Commit Messages](#git-commit-messages)
+- [Go Styleguide](#go-styleguide)
+
+[Additional Notes](#additional-notes)
+
+## How Can I Contribute?
+
+### Reporting Bugs
+
+#### Before Submitting A Bug Report
+
+- **Search existing issues** to see if the problem has already been reported.
+  If it has **and the issue is still open**, add a comment to the existing issue instead of opening a new one.
+
+#### How Do I Submit A (Good) Bug Report?
+
+Explain the problem and include additional details to help maintainers reproduce the problem:
+
+- **Use a clear and descriptive title** for the issue to identify the problem.
+- **Describe the exact steps which reproduce the problem** in as many details as possible.
+  When listing steps, **don't just say what you did, but explain how you did it**.
+- **Provide specific examples to demonstrate the steps**.
+  Include links to files or GitHub projects, or copy/pasteable snippets, which you use in those examples.
+  If you're providing snippets in the issue,
+  use [Markdown code blocks](https://help.github.com/articles/markdown-basics/#multiple-lines).
+- **Describe the behavior you observed after following the steps** and point out what exactly is the problem with that behavior.
+- **Explain which behavior you expected to see instead and why.**
+- **Include error messages and stack traces** which show the output / crash and clearly demonstrate the problem.
+
+Provide more context by answering these questions:
+
+- **Can you reliably reproduce the issue?** If not, provide details about how often the problem happens
+  and under which conditions it normally happens.
+
+Include details about your configuration and environment:
+
+- **What is the version of the Atree you're using**?
+- **What's the name and version of the Operating System you're using**?
+
+### Suggesting Enhancements
+
+#### Before Submitting An Enhancement Suggestion
+
+- **Perform a cursory search** to see if the enhancement has already been suggested.
+  If it has, add a comment to the existing issue instead of opening a new one.
+
+#### How Do I Submit A (Good) Enhancement Suggestion?
+
+Enhancement suggestions are tracked as [GitHub issues](https://guides.github.com/features/issues/).
+Create an issue and provide the following information:
+
+- **Use a clear and descriptive title** for the issue to identify the suggestion.
+- **Provide a step-by-step description of the suggested enhancement** in as many details as possible.
+- **Provide specific examples to demonstrate the steps**.
+  Include copy/pasteable snippets which you use in those examples,
+  as [Markdown code blocks](https://help.github.com/articles/markdown-basics/#multiple-lines).
+- **Describe the current behavior** and **explain which behavior you expected to see instead** and why.
+- **Explain why this enhancement would be useful** to Atree users.
+
+### Your First Code Contribution
+
+Unsure where to begin contributing to Atree?
+You can start by looking through these "Good first issue" and "Help wanted" issues:
+
+- [Good first issues](https://github.com/onflow/atree/labels/good%20first%20issue):
+  issues which should only require a few lines of code, and a test or two.
+- [Help wanted issues](https://github.com/onflow/atree/labels/help%20wanted):
+  issues which should be a bit more involved than "Good first issue" issues.
+
+Both issue lists are sorted by total number of comments.
+While not perfect, number of comments is a reasonable proxy for impact a given change will have.
+
+### Pull Requests
+
+The process described here has several goals:
+
+- Maintain code quality
+- Fix problems that are important to users
+- Engage the community in working toward the best possible Atree UX
+- Enable a sustainable system for the Atree's maintainers to review contributions
+
+Please follow the [styleguides](#styleguides) to have your contribution considered by the maintainers.
+Reviewer(s) may ask you to complete additional design work, tests,
+or other changes before your pull request can be ultimately accepted.
+
+## Styleguides
+
+Before contributing, make sure to examine the project to get familiar with the patterns and style already being used.
+
+### Git Commit Messages
+
+- Use the present tense ("Add feature" not "Added feature")
+- Use the imperative mood ("Move cursor to..." not "Moves cursor to...")
+- Limit the first line to 72 characters or less
+- Reference issues and pull requests liberally after the first line
+
+### Go Styleguide
+
+The majority of this project is written Go.
+
+We try to follow the coding guidelines from the Go community.
+
+- Code should be formatted using `gofmt`
+- Code should pass the linter: `make lint`
+- Code should follow the guidelines covered in
+  [Effective Go](http://golang.org/doc/effective_go.html)
+  and [Go Code Review Comments](https://github.com/golang/go/wiki/CodeReviewComments)
+- Code should be commented
+- Code should pass all tests: `make test`
+
+## Additional Notes
+
+Thank you for your interest in contributing to Atree!