Add some information to README.md along with basic examples

Author: hussainweb

README.md

@@ -1,2 +1,28 @@
 # drupal-code-quality
-https://hub.docker.com/r/hussainweb/drupal-code-quality/
+[Drupal Code Quality](https://hub.docker.com/r/hussainweb/drupal-code-quality/) is a Docker image designed to aid in static analysis for Drupal code bases. It is based off [Adam Culp's PHP Code Quality](https://hub.docker.com/r/adamculp/php-code-quality/) Docker image. Therefore, all tools present in adamculp/php-code-quality are also present here. See [README.md in that package](https://github.com/adamculp/php-code-quality/blob/master/README.md) for more details.
+
+From a Drupal perspective, this Docker image adds:
+- [drupal/coder](https://packagist.org/packages/drupal/coder)
+- [drupalsecure sniffs](http://git.drupal.org/sandbox/coltrane/1921926)
+- [PAReview.sh](https://github.com/klausi/pareviewsh)
+- [codespell](https://github.com/lucasdemarchi/codespell)
+- [eslint](https://github.com/eslint/eslint)
+- [stylelint](https://github.com/stylelint/stylelint)
+
+## Usage
+Run these commands in your repository's root directory. The commands below assume that the Drupal site lives under the `docroot` directory.
+
+### Get to a shell
+This is the simplest command to get into a shell with your code mounted under `/app`.
+
+```
+docker run -it --rm -v "$PWD":/app -w /app hussainweb/drupal-code-quality:latest bash
+```
+
+### Run phpcs with Drupal coder sniffs
+
+```
+docker run -it --rm -v "$PWD":/app -w /app hussainweb/drupal-code-quality:latest phpcs --standard=Drupal --extensions=php,module,inc,install,test,profile,theme docroot/modules/custom/ docroot/themes/custom/
+```
+
+Refer to [adamculp/php-code-quality's Usage](https://github.com/adamculp/php-code-quality/blob/master/README.md#usage) for more details.