Update dbal.rst

Author: stormoPL

doctrine/dbal.rst

@@ -21,7 +21,13 @@ makes it easy to execute queries and perform other database actions.
     Read the official Doctrine `DBAL Documentation`_ to learn all the details
     and capabilities of Doctrine's DBAL library.
 
-To get started, configure the ``DATABASE_URL`` environment variable in ``.env``:
+First, install the Doctrine bundle:
+
+.. code-block:: terminal
+
+    composer require doctrine/doctrine-bundle
+
+Then configure the ``DATABASE_URL`` environment variable in ``.env``:
 
 .. code-block:: text