Add basic CONTRIBUTING.md. Fixes #1794. (#2659)

* Add basic CONTRIBUTING.md. Fixes #1794.

* Mention webtrees.github.io for contributions.

* Add notes on development tools

* Update CONTRIBUTING.md

* Update CONTRIBUTING.md

* Policy for third-party libraries in the source tree.

* Add advice on shallow cloning.

* Typo

1 files changed, 114 insertions, 0 deletions

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+# How to contribute
+
+Thanks for taking the time to contribute!
+
+The following is a set of guidelines for contributing to Webtrees. These are mostly guidelines, not rules. 
+Use your best judgment, and feel free to propose changes to this document in a pull request.
+
+## How to submit a patch or feature
+
+If you want to submit a patch or feature, please create a pull request on Github. There are different branches for different versions of webtrees:
+
+* For webtrees 2.0, use the `master` branch
+* For the latest webtrees 1.7.*, use the `1.7` branch
+
+Before submitting a pull request make sure you have [tested the code](#how-to-test) 
+and [followed the coding conventions](#coding-conventions).
+
+Please read more about [setting up your environment](#how-to-setup-the-environment) for development.
+
+## How to start
+
+You can start contributing by
+
+* submitting patches or features
+* writing tests to [increase the test coverage](https://coveralls.io/github/fisharebest/webtrees?branch=master)
+* creating or updating [translations](#translations)
+* Join our slack. The invitation link will be updated on this line.
+* Help us maintaining our github page from the repository [webtrees.github.io](https://github.com/webtrees/webtrees.github.io).
+
+## How to setup a development environment
+
+You will need three tools, in addition to the requirements of a live installation.
+
+* `git` - to fetch the latest development code, merge changes, create pull requests, etc.
+* [`composer`](https://getcomposer.org) - to install PHP dependencies, build releases, and run tests.
+* [`npm`](https://nodejs.org/en/download/package-manager) - to install CSS/JS dependencies and create portable/minified `.css` / `.js` files.
+
+You do not need to understand the details of `composer` and `npm`.  You just need to be able to type a few commands at a console.
+
+If you are going to submit your work to the project, you will need a basic understanding of `git`.  The workflow for using git is covered below in the section on "Pull Requests".
+
+### GIT
+
+The project has been running for many years, and has a lot of history.
+This means that the full repository is over 600MB.
+
+If you are only interested in the latest version of the code, you can use a
+"shallow clone", which is about 30MB.
+
+Use `git clone --depth 1 https://github.com/fisharebest/webtrees`.
+
+### Composer
+
+The instructions below assume you have created an alias/shortcut for `composer`.
+If not, you'll need to replace `composer` with `php /path/to/your/copy/of/composer.phar`.
+
+* You would usually run `composer install` before starting any develoment.  This loads all the development tools, including the PHP debug bar, the build scripts, the analysis and testing tools.  You would then run `composer install --no-dev` before committing any changes.
+
+* The PHP Debug Bar can set a large number of HTTP headers, and you may need to increase the size of buffers in your webserver configuration.  There are some notes in the file `app/Http/Middleware/UseDebugbar.php`.
+
+* You can use a "pre-commit hook" to run checks on your code before you commit them to your local repository.  To do this, rename the file `.git/hooks/pre-commit.sample` to `.git/hooks/pre-commit` and then add this line at the end of the file: `composer webtrees:pre-commit-hook`. 
+
+### NPM
+
+* After modifying any CSS or JS files, you'll need to rebuild the files in `public/js` and `public/css`.  You do this with the command `npm run production`.
+
+## Third-party libraries and compiled files in the source tree
+
+For historic reasons, we include certain third-party libraries and compiled
+files in our source tree.  This is usually considered to be bad practice.
+We do it because we have a large number of testers and users who have become
+accustomed to downloading the latest source code and running it without any build step.
+
+We include the non-development PHP libraries from `/vendor`.
+These are created using the command `composer install --no-dev`.
+
+We include the compiled JS and CSS assets from `/public/{css,js}`).
+These are created using the command `npm run production`.
+
+
+## Creating a pull request
+
+[TODO]
+
+
+
+1. Fork and clone the repository
+2. Run `composer install` to update the PHP dependencies.
+3. Run `npm install` to update the JS and HTML files.
+4. Run `php -S localhost:8080` and open your browser at [localhost:8080](http://localhost:8080)
+5. Go through the install process
+
+## How to test
+
+Install PHPUnit by running `composer install`
+
+Then run the tests with `vendor/bin/phpunit`
+
+## Coding conventions
+
+Your code should follow the [PSR-12](https://www.php-fig.org/psr/psr-12/) Extended coding style guide.
+
+Please do not contribute your IDE directories (e.g. `.idea` or `.vscode`).
+
+## Translations
+
+Please refer to the guide from the [official wiki](https://wiki.webtrees.net/en/Category:Translation_Guidelines).
+
+There is a [translators forum](http://webtrees.net/index.php/en/forum/8-translation) where you can discuss any issues relating to translation.
+
+Updates to translations should be made at [translate.webtrees.net](https://translate.webtrees.net). 
+Changes made there will be pushed to webtrees git repository periodically and will be available 
+on the development version of webtrees. They will be included in the next release of webtrees.
+