Documented the framework.session.enabled option

Author: javiereguiluz

reference/configuration/framework.rst

@@ -147,6 +147,7 @@ Configuration
   * `cookie_lifetime`_
   * `cookie_path`_
   * `cookie_secure`_
+  * :ref:`enabled <reference-session-enabled>`
   * `gc_divisor`_
   * `gc_maxlifetime`_
   * `gc_probability`_
@@ -959,6 +960,49 @@ session persists.
 Starting in Symfony 3.4, session data is *only* written when the session data has
 changed. Previously, you needed to set this option to avoid that behavior.
 
+.. _reference-session-enabled:
+
+enabled
+.......
+
+**type**: ``boolean`` **default**: ``true``
+
+Whether to enable the session support in the framework.
+
+.. configuration-block::
+
+    .. code-block:: yaml
+
+        # app/config/config.yml
+        framework:
+            session:
+                enabled: true
+
+    .. code-block:: xml
+
+        <!-- app/config/config.xml -->
+        <?xml version="1.0" encoding="UTF-8" ?>
+        <container xmlns="http://symfony.com/schema/dic/services"
+            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+            xmlns:framework="http://symfony.com/schema/dic/symfony"
+            xsi:schemaLocation="http://symfony.com/schema/dic/services
+                http://symfony.com/schema/dic/services/services-1.0.xsd
+                http://symfony.com/schema/dic/symfony http://symfony.com/schema/dic/symfony/symfony-1.0.xsd">
+
+            <framework:config>
+                <framework:session enabled="true" />
+            </framework:config>
+        </container>
+
+    .. code-block:: php
+
+        // app/config/config.php
+        $container->loadFromExtension('framework', array(
+            'session' => array(
+                'enabled' => true,
+            ),
+        ));
+
 assets
 ~~~~~~