Added docs to add custom hydrator strategy by example

docs/strategies.rst

@@ -5,7 +5,7 @@ Hydrator Strategies
 Some hydrator strategies are supplied with this library.  You may also add your own hydrator
 strategies.
 
-All strategies are in the namespace ``ApiSkeletons\Doctrine\ORM\GraphQL\Hydrator\Strategy``
+Included strategies are in the namespace ``ApiSkeletons\Doctrine\ORM\GraphQL\Hydrator\Strategy``
 
 FieldDefault
 ============
@@ -31,6 +31,66 @@ ToBoolean
 Similar to ``ToInteger``, this will convert the field value to a boolean to be handled as a boolean internal to PHP.
 
 
+Add a custom hydrator strategy
+==============================
+
+To add a custom hydrator strategy, create a class that implements the interface
+``Laminas\Hydrator\Strategy\StrategyInterface``.  Add the class to the
+hydrator strategy container after creating the driver.
+
+.. code-block:: php
+
+    use ApiSkeletons\Doctrine\ORM\GraphQL\Driver;
+    use ApiSkeletons\Doctrine\ORM\GraphQL\Hydrator\HydratorContainer;
+    use App\GraphQL\Hydrator\Strategy\S3Url;
+
+    $driver = new Driver($entityManager);
+
+    $driver->get(HydratorContainer::class)
+        ->set(S3Url::class, static fn () => new S3Url());
+
+The S3Url class would look something like this:
+
+.. code-block:: php
+
+    namespace App\GraphQL\Hydrator\Strategy;
+
+    use Illuminate\Support\Facades\Storage;
+    use Laminas\Hydrator\Strategy\StrategyInterface;
+
+    /**
+     * Resolve the token to an S3 url
+     */
+    class S3Url implements
+        StrategyInterface
+    {
+        public function extract(mixed $value, object|null $object = null): mixed
+        {
+            if (! $value) {
+                return $value;
+            }
+
+            return Storage::disk('s3')->url($value);
+        }
+
+        /**
+         * This library does not hydrate using the hydrator but this method is required
+         * @param mixed[]|null $data
+         */
+        public function hydrate(mixed $value, array|null $data): mixed
+        {
+            return $value;
+        }
+    }
+
+Then add the hydratorStrategy to the entity field you wish to custom extract.
+
+.. code-block:: php
+
+    #[GraphQL\Field(hydratorStrategy: S3Url::class)]
+    #[ORM\Column(type: "text", nullable: true)]
+    public $favicon;
+
 .. role:: raw-html(raw)
    :format: html