[README] bit info added

README.md

@@ -32,28 +32,85 @@ This tool will *reconstruct* (change) your code - **run it only in a new clean g
 composer require rector/rector --dev
 ```
 
-## Use
+## Use (WIP)
 
 ```bash
-vendor/bin/rector reconstruct src
+vendor/bin/rector reconstruct src --framework Nette --to-version 2.4
+vendor/bin/rector reconstruct src --framework Symfony --to-version 3.3
 ```
 
+
+### How to Add New Rector
+
+Just extend `Rector\Rector\AbstractRector`.
+It will prepare **4 methods** - 2 informative and 2 processing the node.
+
+```php
+/**
+ * A project that is related to this.
+ * E.g "Nette", "Symfony"
+ * Use constants from @see SetNames, if possible.
+ */
+public function getSetName(): string
+{
+}
+
+/**
+ * Version this deprecations is active since.
+ * E.g. 2.3.
+ */
+public function sinceVersion(): float
+{
+}
+
+public function isCandidate(Node $node): bool
+{
+}
+
+public function refactor(Node $node): ?Node
+{
+}
+```
+
+2. Put it under `namespace Rector\Contrib\<set>;` namespace
+
+```php
+<?php declare(strict_types=1);
+
+namespace Rector\Contrib\Symfony;
+    
+use Rector\Rector\AbstractRector;
+
+final class MyRector extends AbstractRector
+{
+    // ...
+}
+```
+
+3. Add a Test Case
+
+4. Submit PR
+ 
+5. :check: 
+
+
+
 ### How to Contribute
 
 Just follow 3 rules:
 
 - **1 feature per pull-request**
-- **New feature needs tests**. [Coveralls.io](https://coveralls.io/) checks code coverage under every PR.
+- **New feature needs tests**
 - Tests, coding standard and PHPStan **checks must pass**
 
     ```bash
     composer all
     ```
 
-    Often you don't need to fix coding standard manually, just run:
+    Don you need to fix coding standards? Run:
 
     ```bash
-    composer fs
+    composer fix-cs
     ```
 
 We would be happy to merge your feature then.