feature #3454 [Security] Add host option (ghostika)

This PR was merged into the 2.4 branch.

Discussion
----------

[Security] Add host option

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | 2.4+
| Fixed tickets | #3453

Host option is missing from documentation and this feature was introduced in 2.4 for the firewall.

Commits
-------

6cba192 remove versionadded from book and fix words
3e42b84 Add versionadded tag to security config reference, reference cookbok entry in book
cc8d19a line break
0244173 add host to the config page
4fb6e59 Add host config to the security documentation

Author: weaverryan

Diff for: book/security.rst

@@ -1098,7 +1098,7 @@ Thanks to the SensioFrameworkExtraBundle, you can also secure your controller us
         // ...
     }
 
-For more information, see the 
+For more information, see the
 :doc:`FrameworkExtraBundle documentation </bundles/SensioFrameworkExtraBundle/annotations/security>`.
 
 Securing other Services
@@ -2164,6 +2164,7 @@ Learn more from the Cookbook
 * :doc:`Blacklist users by IP address with a custom voter </cookbook/security/voters>`
 * :doc:`Access Control Lists (ACLs) </cookbook/security/acl>`
 * :doc:`/cookbook/security/remember_me`
+* :doc:`How to Restrict Firewalls to a Specific Host </cookbook/security/host_restriction>`
 
 .. _`FOSUserBundle`: https://github.com./FriendsOfSymfony/FOSUserBundle
 .. _`implement the \Serializable interface`: http://php.net/manual/en/class.serializable.php

Diff for: cookbook/security/host_restriction.rst

@@ -5,7 +5,7 @@ How to Restrict Firewalls to a Specific Host
 ============================================
 
 .. versionadded:: 2.4
-    Support for restricting security firewalls to a specific host was added in
+    Support for restricting security firewalls to a specific host was introduced in
     Symfony 2.4.
 
 When using the Security component, you can create firewalls that match certain

Diff for: reference/configuration/security.rst

@@ -13,6 +13,10 @@ Full Default Configuration
 The following is the full default configuration for the security system.
 Each part will be explained in the next section.
 
+.. versionadded:: 2.4
+    Support for restricting security firewalls to a specific host was introduced in
+    Symfony 2.4.
+
 .. configuration-block::
 
     .. code-block:: yaml
@@ -98,6 +102,8 @@ Each part will be explained in the next section.
                 # Examples:
                 somename:
                     pattern: .*
+                    # restrict the firewall to a specific host
+                    host: admin\.example\.com
                     request_matcher: some.service.id
                     access_denied_url: /foo/error403
                     access_denied_handler: some.service.id