Added tip at a more logical place

Author: wouterj

book/doctrine.rst

@@ -517,6 +517,16 @@ of the bundle:
     If you're following along with this example, you'll need to create a
     route that points to this action to see it work.
 
+.. tip::
+
+    This page shows working with Doctrine within a controller. You may also
+    want to work with Doctrine elsewhere in your application. The
+    :method:`Symfony\\Bundle\\FrameworkBundle\\Controller\\Controller::getDoctrine`
+    method of the controller returns the ``doctrine`` service, you can work with
+    this in the same way elsewhere by injecting this into your own
+    services. See :doc:`/book/service_container` for more on creating
+    your own services.
+
 Take a look at the previous example in more detail:
 
 * **lines 9-12** In this section, you instantiate and work with the ``$product``