Improve the readme

ApiDocGenerator.php

@@ -27,7 +27,7 @@ class ApiDocGenerator
         $this->describers = $describers;
     }
 
-    public function extract(): Swagger
+    public function generate(): Swagger
     {
         if (null !== $this->swagger) {
             return $this->swagger;

README.md

@@ -1,2 +1,61 @@
 # ApiDocBundle
+
 [WIP] Generates Swagger docs from several sources
+
+## Installation
+
+Just like any bundle, you have to download it using composer:
+```
+composer require exsyst/api-doc-bundle dev-master
+```
+
+And then add it to your kernel:
+```php
+class AppKernel extends Kernel
+{
+    public function registerBundles()
+    {
+        $bundles = [
+            // ...
+
+            new EXSyst\Bundle\ApiDocBundle\ApiDocBundle(),
+        ];
+
+        // ...
+    }
+}
+```
+
+And that's all, no configuration needed!
+
+## What does this bundle?
+
+It generates you a swagger documentation from your symfony app thanks to
+different sources called _Describers_. These _Describers_ are specific
+to a library and extract data from it and merge it into your swagger
+documentation.
+
+You can fetch your swagger documentation in your app:
+```php
+$generator = $container->get('exsyst_api_doc.generator');
+$swagger = $generator->generate()->toArray();
+```
+
+## What's supported?
+
+This bundle supports _Symfony_ route requirements, PHP annotations,
+[_Swagger-Php_](https://github.com/zircote/swagger-php) annotations,
+[_NelmioApiDocBundle_](https://github.com/nelmio/NelmioApiDocBundle) annotation,
+[_FOSRestBundle_](https://github.com/FriendsOfSymfony/FOSRestBundle) annotations and
+[_Api-Platform_](https://github.com/api-platform/api-platform) apps.
+
+This bundle is a **Work In Progress** and as such it does only support input
+documentation for now (if you use _Swagger-Php_ or _Api-Platform_ output is supported as well).
+
+## What's next?
+
+The hardest part remain: **models**. We have to build something to
+manage models that can vary based on several factors (serialization
+groups, class, etc.) and then put it in the app's documentation.
+
+Other libraries support might be added but the priority is to finalize the bundle first.