Added manual chapter on PSR-11 support

Author: weierophinney

doc/book/psr-11.md

@@ -0,0 +1,58 @@
+# PSR-11 Support
+
+[container-interop/container-interop 1.2.0](https://github.com/container-interop/container-interop/releases/tag/1.2.0)
+modifies its codebase to extend interfaces [psr/container](https://github.com/php-fig/container)
+(the official interfaces for [PSR-11](http://www.php-fig.org/psr/psr-11/)). If
+you are on a pre-3.3.0 version of zend-servicemanager, update your project, and
+receive container-interop 1.2, then zend-servicemanager can already act as a
+PSR-11 provider!
+
+zend-servicemanager 3.3.0 requires at least version 1.2 of container-interop,
+and _also_ requires psr/container 1.0 to explicitly signal that it is a PSR-11
+provider, and to allow removal of the container-interop dependency later.
+
+Version 4.0 will require only psr/container, and will update the various factory
+interfaces and exception implementations to typehint against the PSR-11
+interfaces, which will require changes to any implementations you have. In the
+meantime, you can [duck-type](https://en.wikipedia.org/wiki/Duck_typing) the
+following factory types:
+
+- `Zend\ServiceManager\Factory\FactoryInterface`: use a callable with the
+  following signature:
+
+  ```php
+  function (
+      \Psr\Container\ContainerInterface $container,
+      string $requestedName,
+      array $options = null
+  )
+  ```
+
+- `Zend\ServiceManager\Factory\DelegatorFactoryInterface`: use a callable with
+  the following signature:
+
+  ```php
+  function (
+      \Psr\Container\ContainerInterface $container,
+      string $name,
+      callable $callback,
+      array $options = null
+  )
+  ```
+
+- `Zend\ServiceManager\Initializer\InitializerInterface`: use a callable with
+  the following signature:
+
+  ```php
+  function (
+      \Psr\Container\ContainerInterface $container,
+      $instance
+  )
+  ```
+
+Abstract factories _can not_ be duck typed, due to the additional `canCreate()`
+method.
+
+You can also leave your factories as-is for now, and update them once
+zend-servicemanager v4.0 is released, at which time we will be providing tooling
+to help migrate your factories to PSR-11.

mkdocs.yml

@@ -4,6 +4,7 @@ pages:
     - index.md
     - 'Quick Start': quick-start.md
     - Reference:
+      - 'PSR-11 Support': psr-11.md
       - 'Configuring the service manager': configuring-the-service-manager.md
       - Delegators: delegators.md
       - 'Lazy services': lazy-services.md