Update readme (#36)

README.md

@@ -2,18 +2,41 @@
     <a href="https://github.com/yiisoft" target="_blank">
         <img src="https://avatars0.githubusercontent.com/u/993323" height="100px">
     </a>
-    <h1 align="center">Yii String Helper</h1>
+    <h1 align="center">Yii Strings</h1>
     <br>
 </p>
 
 The Yii string helper provides:
 
-- static methods allowing to deal with strings more efficiently;
-- Inflector helper pluralizes and singularizes English nouns.
+- StringHelper that has static methods allowing dealing with strings more efficiently;
+- Inflector provides methods such as `pluralize()` or `slug()` that derive a new string based on the string given.
 
 [![Latest Stable Version](https://poser.pugx.org/yiisoft/strings/v/stable.png)](https://packagist.org/packages/yiisoft/strings)
 [![Total Downloads](https://poser.pugx.org/yiisoft/strings/downloads.png)](https://packagist.org/packages/yiisoft/strings)
 [![Build Status](https://github.com/yiisoft/strings/workflows/build/badge.svg)](https://github.com/yiisoft/strings/actions)
 [![Scrutinizer Code Quality](https://scrutinizer-ci.com/g/yiisoft/strings/badges/quality-score.png?b=master)](https://scrutinizer-ci.com/g/yiisoft/strings/?branch=master)
 [![Code Coverage](https://scrutinizer-ci.com/g/yiisoft/strings/badges/coverage.png?b=master)](https://scrutinizer-ci.com/g/yiisoft/strings/?branch=master)
+[![Mutation testing badge](https://img.shields.io/endpoint?style=flat&url=https%3A%2F%2Fbadge-api.stryker-mutator.io%2Fgithub.com%2Fyiisoft%2Fstrings%2Fmaster)](https://dashboard.stryker-mutator.io/reports/github.com/yiisoft/strings/master)
+[![static analysis](https://github.com/yiisoft/strings/workflows/static%20analysis/badge.svg)](https://github.com/yiisoft/strings/actions?query=workflow%3A%22static+analysis%22)
 
+## Installation
+
+```
+composer require yiisoft/strings
+```
+
+## General usage
+
+StringHelper methods are static so usage is like the following:
+
+```php
+echo \Yiisoft\Strings\StringHelper::countWords('Strings are cool!'); // 3
+```
+
+Inflector usage is the following:
+
+```php
+echo (new \Yiisoft\Strings\Inflector())->withoutIntl()->slug('Strings are cool!'); // strings-are-cool
+```
+
+Check both classes to find out about the methods available.