Updated all the README files

Author: javiereguiluz

README.md

@@ -1,23 +1,18 @@
 Security Component
 ==================
 
-Security provides an infrastructure for sophisticated authorization systems,
-which makes it possible to easily separate the actual authorization logic from
-so called user providers that hold the users credentials. It is inspired by
-the Java Spring framework.
+The Security component provides a complete security system for your web
+application. It ships with facilities for authenticating using HTTP basic or
+digest authentication, interactive form login or X.509 certificate login, but
+also allows you to implement your own authentication strategies. Furthermore,
+the component provides ways to authorize authenticated users based on their
+roles, and it contains an advanced ACL system.
 
 Resources
 ---------
 
-Documentation:
-
-https://symfony.com/doc/2.3/book/security.html
-
-Resources
----------
-
-You can run the unit tests with the following command:
-
-    $ cd path/to/Symfony/Component/Security/
-    $ composer install
-    $ phpunit
+  * [Documentation](https://symfony.com/doc/current/components/security/index.html)
+  * [Contributing](https://symfony.com/doc/current/contributing/index.html)
+  * [Report issues](https://github.com/symfony/symfony/issues) and
+    [send Pull Requests](https://github.com/symfony/symfony/pulls)
+    in the [main Symfony repository](https://github.com/symfony/symfony)