minor #834 [doc] Create doc for RememberMeServiceProvider (GromNaN)

This PR was squashed before being merged into the master branch (closes #834).

Discussion
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[doc] Create doc for RememberMeServiceProvider

Refs #689

Commits
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f79177eb [doc] Create doc for RememberMeServiceProvider

doc/providers.rst

@@ -65,6 +65,7 @@ the ``Silex\Provider`` namespace:
 * :doc:`HttpCacheServiceProvider <providers/http_cache>`
 * :doc:`FormServiceProvider <providers/form>`
 * :doc:`SecurityServiceProvider <providers/security>`
+* :doc:`RememberMeServiceProvider <providers/remember_me>`
 * :doc:`ServiceControllerServiceProvider <providers/service_controller>`
 
 Third party providers

doc/providers/remember_me.rst

+RememberMeServiceProvider
+=========================
+
+The *RememberMeServiceProvider* adds "Remember-Me" authentication to the
+*SecurityServiceProvider*.
+
+Parameters
+----------
+
+n/a
+
+Services
+--------
+
+n/a
+
+.. note::
+
+    The service provider defines many other services that are used internally
+    but rarely need to be customized.
+
+
+Registering
+-----------
+
+Before registering this service provider, you must register the *SecurityServiceProvider*.
+
+.. code-block:: php
+
+    $app->register(new Silex\Provider\SecurityServiceProvider());
+    $app->register(new Silex\Provider\RememberMeServiceProvider());
+
+    $app['security.firewalls'] = array(
+        'my-firewall' => array(
+            'pattern'     => '^/secure$',
+            'form'        => true,
+            'logout'      => true,
+            'remember_me' => array(
+                'key'                => 'Choose_An_Unique_Random_Key',
+                'always_remember_me' => true,
+                /* Other options */
+            ),
+            'users' => array( /* ... */ ),
+        ),
+    );
+
+Options
+-------
+
+* **key**: A secret key to generate tokens (you should generate a random string).
+
+* **name**: Cookie name (default: ``REMEMBERME``).
+
+* **lifetime**: Cookie lifetime (default: ``31536000`` = ~1 year).
+
+* **path**: Cookie path (default: ``/``).
+
+* **domain**: Cookie domain (default: ``null`` = request domain).
+
+* **secure**: Cookie is secure (default: ``false``).
+
+* **httponly**: Cookie is HTTP only (default: ``true``)
+
+* **always_remember_me**: Enable remember me (default: ``false``)
+
+* **remember_me_parameter**: (default: ``_remember_me``). Name of the request
+paramater enabling remember_me on login. To add the checkbox to the login form.
+You can find more information in the `Symfony cookbook <http://symfony.com/doc/current/cookbook/security/remember_me.html>
+