Restored the Assetic tags because they are removed in another PR

Author: javiereguiluz

reference/dic_tags.rst

@@ -15,6 +15,13 @@ may also be tags in other bundles you use that aren't listed here.
 ========================================  ========================================================================
 Tag Name                                  Usage
 ========================================  ========================================================================
+`assetic.asset`_                          Register an asset to the current asset manager
+`assetic.factory_worker`_                 Add a factory worker
+`assetic.filter`_                         Register a filter
+`assetic.formula_loader`_                 Add a formula loader to the current asset manager
+`assetic.formula_resource`_               Adds a resource to the current asset manager
+`assetic.templating.php`_                 Remove this service if PHP templating is disabled
+`assetic.templating.twig`_                Remove this service if Twig templating is disabled
 `auto_alias`_                             Define aliases based on the value of container parameters
 `console.command`_                        Add a command
 `controller.argument_value_resolver`_     Register a value resolver for controller arguments such as ``Request``
@@ -49,6 +56,182 @@ Tag Name                                  Usage
 `validator.initializer`_                  Register a service that initializes objects before validation
 ========================================  ========================================================================
 
+assetic.asset
+-------------
+
+**Purpose**: Register an asset with the current asset manager
+
+assetic.factory_worker
+----------------------
+
+**Purpose**: Add a factory worker
+
+A Factory worker is a class implementing ``Assetic\Factory\Worker\WorkerInterface``.
+Its ``process($asset)`` method is called for each asset after asset creation.
+You can modify an asset or even return a new one.
+
+In order to add a new worker, first create a class::
+
+    use Assetic\Asset\AssetInterface;
+    use Assetic\Factory\Worker\WorkerInterface;
+
+    class MyWorker implements WorkerInterface
+    {
+        public function process(AssetInterface $asset)
+        {
+            // ... change $asset or return a new one
+        }
+
+    }
+
+And then register it as a tagged service:
+
+.. configuration-block::
+
+    .. code-block:: yaml
+
+        services:
+            App\Assetic\CustomWorker:
+                tags: [assetic.factory_worker]
+
+    .. code-block:: 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"
+            xsi:schemaLocation="http://symfony.com/schema/dic/services
+                http://symfony.com/schema/dic/services/services-1.0.xsd">
+
+            <services>
+                <service id="App\Assetic\CustomWorker">
+                    <tag name="assetic.factory_worker" />
+                </service>
+            </services>
+        </container>
+
+    .. code-block:: php
+
+        use App\Assetic\CustomWorker;
+
+        $container
+            ->register(CustomWorker::class)
+            ->addTag('assetic.factory_worker')
+        ;
+
+assetic.filter
+--------------
+
+**Purpose**: Register a filter
+
+AsseticBundle uses this tag to register common filters. You can also use
+this tag to register your own filters.
+
+First, you need to create a filter::
+
+    use Assetic\Asset\AssetInterface;
+    use Assetic\Filter\FilterInterface;
+
+    class MyFilter implements FilterInterface
+    {
+        public function filterLoad(AssetInterface $asset)
+        {
+            $asset->setContent('alert("yo");' . $asset->getContent());
+        }
+
+        public function filterDump(AssetInterface $asset)
+        {
+            // ...
+        }
+    }
+
+Second, define a service:
+
+.. configuration-block::
+
+    .. code-block:: yaml
+
+        services:
+            App\Assetic\CustomFilter:
+                tags:
+                    - { name: assetic.filter, alias: my_filter }
+
+    .. code-block:: 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"
+            xsi:schemaLocation="http://symfony.com/schema/dic/services
+                http://symfony.com/schema/dic/services/services-1.0.xsd">
+
+            <services>
+                <service id="App\Assetic\CustomFilter">
+                    <tag name="assetic.filter" alias="my_filter" />
+                </service>
+            </services>
+        </container>
+
+    .. code-block:: php
+
+        use App\Assetic\CustomFilter;
+
+        $container
+            ->register(CustomFilter::class)
+            ->addTag('assetic.filter', array('alias' => 'my_filter'))
+        ;
+
+Finally, apply the filter:
+
+.. code-block:: twig
+
+    {% javascripts
+        '@AcmeBaseBundle/Resources/public/js/global.js'
+        filter='my_filter'
+    %}
+        <script src="{{ asset_url }}"></script>
+    {% endjavascripts %}
+
+You can also apply your filter via the ``assetic.filters.my_filter.apply_to``
+config option as it's described here: :doc:`/frontend/assetic/apply_to_option`.
+In order to do that, you must define your filter service in a separate xml
+config file and point to this file's path via the ``assetic.filters.my_filter.resource``
+configuration key.
+
+assetic.formula_loader
+----------------------
+
+**Purpose**: Add a formula loader to the current asset manager
+
+A Formula loader is a class implementing
+``Assetic\\Factory\Loader\\FormulaLoaderInterface`` interface. This class
+is responsible for loading assets from a particular kind of resources (for
+instance, twig template). Assetic ships loaders for PHP and Twig templates.
+
+An ``alias`` attribute defines the name of the loader.
+
+assetic.formula_resource
+------------------------
+
+**Purpose**: Adds a resource to the current asset manager
+
+A resource is something formulae can be loaded from. For instance, Twig
+templates are resources.
+
+assetic.templating.php
+----------------------
+
+**Purpose**: Remove this service if PHP templating is disabled
+
+The tagged service will be removed from the container if the
+``framework.templating.engines`` config section does not contain php.
+
+assetic.templating.twig
+-----------------------
+
+**Purpose**: Remove this service if Twig templating is disabled
+
+The tagged service will be removed from the container if
+``framework.templating.engines`` config section does not contain ``twig``.
+
 auto_alias
 ----------