📚 Readme: add installation instructions

Add badges, installation instructions, a contributing section and license information to the Readme.

Author: jrfnl

README.md

@@ -1,2 +1,70 @@
-# PHPCSDevTools
-Tools for PHP_CodeSniffer sniff developers
+PHPCSDevTools for developers of PHP_CodeSniffer sniffs
+=====================================================
+
+[![Latest Stable Version](https://poser.pugx.org/phpcsstandards/phpcsdevtools/v/stable)](https://packagist.org/packages/phpcsstandards/phpcsdevtools)
+[![Travis Build Status](https://travis-ci.com/PHPCSStandards/PHPCSDevTools.svg?branch=master)](https://travis-ci.com/PHPCSStandards/PHPCSDevTools/branches)
+[![Release Date of the Latest Version](https://img.shields.io/github/release-date/PHPCSStandards/PHPCSDevTools.svg?maxAge=1800)](https://github.com/PHPCSStandards/PHPCSDevTools/releases)
+:construction:
+[![Latest Unstable Version](https://img.shields.io/badge/unstable-dev--develop-e68718.svg?maxAge=2419200)](https://packagist.org/packages/phpcsstandards/phpcsdevtools#dev-develop)
+[![Travis Build Status](https://travis-ci.com/PHPCSStandards/PHPCSDevTools.svg?branch=develop)](https://travis-ci.com/PHPCSStandards/PHPCSDevTools/branches)
+[![Last Commit to Unstable](https://img.shields.io/github/last-commit/PHPCSStandards/PHPCSDevTools/develop.svg)](https://github.com/PHPCSStandards/PHPCSDevTools/commits/develop)
+
+[![Minimum PHP Version](https://img.shields.io/packagist/php-v/phpcsstandards/phpcsdevtools.svg?maxAge=3600)](https://packagist.org/packages/phpcsstandards/phpcsdevtools)
+[![Tested on PHP 5.4 to 7.4 snapshot](https://img.shields.io/badge/tested%20on-PHP%205.4%20|%205.5%20|%205.6%20|%207.0%20|%207.1%20|%207.2%20|%207.3%20|%207.4snapshot-brightgreen.svg?maxAge=2419200)](https://travis-ci.com/PHPCSStandards/PHPCSDevTools)
+
+[![License: LGPLv3](https://poser.pugx.org/phpcsstandards/phpcsdevtools/license.png)](https://github.com/PHPCSStandards/PHPCSDevTools/blob/master/LICENSE)
+![Awesome](https://img.shields.io/badge/awesome%3F-yes!-brightgreen.svg)
+
+
+This is a set of tools to aid developers of sniffs for [PHP CodeSniffer](https://github.com/squizlabs/PHP_CodeSniffer).
+
+* [Installation](#installation)
+    + [Composer Project-based Installation](#composer-project-based-installation)
+    + [Composer Global Installation](#composer-global-installation)
+    + [Stand-alone Installation](#stand-alone-installation)
+* [Contributing](#contributing)
+* [License](#license)
+
+
+Installation
+-------------------------------------------
+
+### Composer Project-based Installation
+
+Run the following from the root of your project:
+```bash
+composer require phpcsstandards/phpcsdevtools:^1.0
+```
+
+### Composer Global Installation
+
+If you work on several different sniff repos, you may want to install this toolset globally:
+```bash
+composer global require phpcsstandards/phpcsdevtools:^1.0
+```
+
+### Stand-alone Installation
+
+* Install [PHP CodeSniffer](https://github.com/squizlabs/PHP_CodeSniffer) via [your preferred method](https://github.com/squizlabs/PHP_CodeSniffer#installation).
+* Register the path to PHPCS in your system `$PATH` environment variable to make the `phpcs` command available from anywhere in your file system.
+* Download the [latest PHPCSDevTools release](https://github.com/PHPCSStandards/PHPCSDevTools/releases) and unzip/untar it into an arbitrary directory.
+    You can also choose to clone this repository using git.
+* Add the path to the directory in which you placed your copy of the PHPCSDevTools repo to the PHP CodeSniffer configuration using the below command:
+   ```bash
+   phpcs --config-set installed_paths /path/to/PHPCSDevTools
+   ```
+   **Warning**: :warning: The `installed_paths` command overwrites any previously set `installed_paths`. If you have previously set `installed_paths` for other external standards, run `phpcs --config-show` first and then run the `installed_paths` command with all the paths you need separated by comma's, i.e.:
+   ```bash
+   phpcs --config-set installed_paths /path/1,/path/2,/path/3
+   ```
+
+
+Contributing
+-------
+Contributions to this project are welcome. Just clone the repo, branch off from `develop`, make your changes, commit them and send in a pull request.
+
+If unsure whether the changes you are proposing would be welcome, open an issue first to discuss your proposal.
+
+License
+-------
+This code is released under the GNU Lesser General Public License (LGPLv3). For more information, visit http://www.gnu.org/copyleft/lesser.html