Switch the doc example to use group instead of chain for long running tasks

docs/development/tech_docu/celery.md

@@ -81,7 +81,7 @@ Example implementation for a celery chain:
 
 ```python
 from allianceauth.services.hooks import get_extension_logger
-from celery import shared_task, chain
+from celery import shared_task, group
 
 logger = get_extension_logger(__name__)
 
@@ -98,18 +98,23 @@ def long_runner():
         task_signature = example.si()
         my_tasks.append(task_signature)
 
-    chain(my_tasks).delay()
+    group(my_tasks).delay()
 ```
 
 In this example, we first add 10 example tasks that need to run one after the other to a list. This can be done by creating a so-called signature for a task. Those signatures are a kind of wrapper for tasks and can be used in various ways to compose work flow for tasks.
 
 The list of task signatures is then converted to a chain and started asynchronously.
 
+:::{note}
+In this example we import group to execute all tasks independently.
+If you wish to run them in order (and stop if a tasks fail) you can use `celery.chain` instead of `celery.group`
+
+For more information on signature and work flows see the official documentation on [Canvas](https://docs.celeryproject.org/en/latest/userguide/canvas.html).
+:::
+
 :::{hint}
 In our example we use ``si()``, which is a shortcut for "immutable signatures" and prevents us from having to deal with result sharing between tasks.
 
-For more information on signature and work flows see the official documentation on `Canvas <https://docs.celeryproject.org/en/latest/userguide/canvas.html>`_.
-
 In this context, please note that Alliance Auth currently only supports chaining because all other variants require a so-called results back, which Alliance Auth does not have.
 :::