Merge #749

749: Contributor guidelines r=Kerollmops a=erlend-sh

Preliminary contributor guidelines, heavily based on the [Vector doc](https://github.com/timberio/vector/blob/master/CONTRIBUTING.md).

Co-authored-by: Erlend Sogge Heggen <e.soghe@gmail.com>

CONTRIBUTING.md

@@ -0,0 +1,112 @@
+# Contributing
+
+First, thank you for contributing to MeiliSearch! The goal of this document is to
+provide everything you need to start contributing to MeiliSearch. The
+following TOC is sorted progressively, starting with the basics and
+expanding into more specifics.
+
+<!-- MarkdownTOC autolink="true" style="ordered" indent="   " -->
+
+1. [Assumptions](#assumptions)
+1. [Your First Contribution](#your-first-contribution)
+1. [Change Control](#change-control)
+   1. [Git Branches](#git-branches)
+   1. [Git Commits](#git-commits)
+      1. [Style](#style)
+   1. [Github Pull Requests](#github-pull-requests)
+      1. [Reviews & Approvals](#reviews--approvals)
+      1. [Merge Style](#merge-style)
+   1. [CI](#ci)
+1. [Development](#development)
+   1. [Setup](#setup)
+   1. [Testing](#testing)
+   1. [Benchmarking](#benchmarking--profiling)
+1. [Humans](#humans)
+   1. [Documentation](#documentation)
+   1. [Changelog](#changelog)
+
+<!-- /MarkdownTOC -->
+
+## Assumptions
+
+1. **You're familiar with [Github](https://github.com) and the [pull request](https://help.github.com/en/github/collaborating-with-issues-and-pull-requests/about-pull-requests)
+   workflow.**
+2. **You've read the MeiliSearch [docs](https://docs.meilisearch.com).**
+3. **You know about the [MeiliSearch community](https://docs.meilisearch.com/resources/contact.html).
+   Please use this for help.**
+
+## Your First Contribution
+
+1. Ensure your change has an issue! Find an
+   [existing issue](https://github.com/meilisearch/meilisearch/issues/) or [open a new issue](https://github.com/meilisearch/meilisearch/issues/new).
+   * This is where you can get a feel if the change will be accepted or not.
+2. Once approved, [fork the MeiliSearch repository](https://help.github.com/en/github/getting-started-with-github/fork-a-repo) in your own
+   Github account.
+3. [Create a new Git branch](https://help.github.com/en/github/collaborating-with-issues-and-pull-requests/creating-and-deleting-branches-within-your-repository)
+4. Review the MeiliSearch [workflow](#workflow) and [development](#development).
+5. Make your changes.
+6. [Submit the branch as a pull request](https://help.github.com/en/github/collaborating-with-issues-and-pull-requests/creating-a-pull-request-from-a-fork) to the main MeiliSearch
+   repo. A MeiliSearch team member should comment and/or review your pull request
+   with a few days. Although, depending on the circumstances, it may take
+   longer.
+
+## Change Control
+
+### Git Branches
+
+_All_ changes must be made in a branch and submitted as [pull requests](#pull-requests).
+MeiliSearch does not adopt any type of branch naming style, but please use something
+descriptive of your changes.
+
+### Git Commits
+
+#### Style
+
+Please ensure your commits are small and focused; they should tell a story of
+your change. This helps reviewers to follow your changes, especially for more
+complex changes.
+
+Familiarise yourself with [How to Write a Git Commit Message](https://chris.beams.io/posts/git-commit/).
+
+### Github Pull Requests
+
+Once your changes are ready you must submit your branch as a pull request.
+
+#### Reviews & Approvals
+
+All pull requests must be reviewed and approved by at least one MeiliSearch team
+member.
+
+#### Merge Style
+
+All pull requests are squashed and merged. We generally discourage large pull
+requests that are over 300-500 lines of diff. If you would like to propose
+a change that is larger we suggest coming onto our chat channel and
+discuss it with one of our engineers. This way we can talk through the
+solution and discuss if a change that large is even needed! This overall
+will produce a quicker response to the change and likely produce code that
+aligns better with our process.
+
+## Development
+
+### Setup
+
+See the [MeiliSearch Docs](https://docs.meilisearch.com/guides/advanced_guides/installation.html) for how to set up a development environment.
+
+### Benchmarking & Profiling
+
+We do not yet do any benchmarking, nor have we formalised our profiling. If you'd like to work on this please get in touch!
+
+## Humans
+
+After making your change, you'll want to prepare it for MeiliSearch users (mostly humans). This usually entails updating documentation and announcing your feature.
+
+### Documentation
+
+Documentation is very important to MeiliSearch. All contributions that
+alter user-facing behavior MUST include documentation changes. Please see
+[GitHub.com/meilisearch/documentation](https://github.com/meilisearch/documentation) for more info.
+
+### Changelog
+
+Until we have guidelines in place, updating the [`Changelog`](/CHANGELOG.md) is solely the responsibility of MeiliSearch team members.