Better README

Author: ondrejmirtes

README.md

@@ -1,9 +1,16 @@
 # PHPStan PSL extension
 
+[![Build](https://github.com/php-standard-library/phpstan-extension/workflows/Build/badge.svg)](https://github.com/php-standard-library/phpstan-extension/actions)
+[![Latest Stable Version](https://poser.pugx.org/php-standard-library/phpstan-extension/v/stable)](https://packagist.org/packages/php-standard-library/phpstan-extension)
+[![License](https://poser.pugx.org/php-standard-library/phpstan-extension/license)](https://packagist.org/packages/php-standard-library/phpstan-extension)
+
+* [PHPStan](https://phpstan.org/)
+* [PSL](https://github.com/azjezz/psl)
+
 ## Description
 
-The main scope of this extension is to help phpstan to detect the types after using `Psl\Type\shape`.
-Its intended to produce the same output as the [psalm plugin](https://github.com/php-standard-library/psalm-plugin).
+The main goal of this extension is to help PHPStan to detect the types after using `Psl\Type\shape`.
+
 Given the following example:
 
 ```php
@@ -22,6 +29,29 @@ $specification = Type\shape([
 $input = $specification->coerce($_GET['user']);
 ```
 
-PhpStan assumes that `$input` is of type `array<"age"|"location"|"name", array<"city"|"country"|"state", string>|int|string>`.
+PHPStan assumes that `$input` is of type `array<"age"|"location"|"name", array<"city"|"country"|"state", string>|int|string>`.
 
 If we enable the extension, you will get a more specific and correct type of `array{name: string, age: int, location?: array{city: string, state: string, country: string}}`.
+
+Besides coerce, this extension also supports `matches()` and `assert()` methods.
+
+## Installation
+
+To use this extension, require it in [Composer](https://getcomposer.org/):
+
+```
+composer require --dev php-standard-library/phpstan-extension
+```
+
+If you also install [phpstan/extension-installer](https://github.com/phpstan/extension-installer) then you're all set!
+
+<details>
+  <summary>Manual installation</summary>
+
+If you don't want to use `phpstan/extension-installer`, include extension.neon in your project's PHPStan config:
+
+```
+includes:
+    - vendor/php-standard-library/phpstan-extension/extension.neon
+```
+</details>