Ported examples over to new config. documented upgrading

docs/upgrading.rst

@@ -0,0 +1,56 @@
+Upgrading to Newer Releases
+===========================
+
+Flask itself is changing like any software is changing over time.  Most of
+the changes are the nice kind, the kind where you don't have th change
+anything in your code to profit from a new release.
+
+However every once in a while there are changes that do require some
+changes in your code or there are changes that make it possible for you to
+improve your own code quality by taking advantage of new features in
+Flask.
+
+This section of the documentation enumerates all the changes in Flask from
+release to release and how you can change your code to have a painless
+updating experience.
+
+Version 0.5
+-----------
+
+Flask 0.5 introduces configuration support and logging as well as
+categories for flashing messages.  All these are features that are 100%
+backwards compatible but you might want to take advantage of them.
+
+Configuration Support
+`````````````````````
+
+The configuration support makes it easier to write any kind of application
+that requires some sort of configuration.  (Which most likely is the case
+for any application out there).
+
+If you previously had code like this::
+
+    app.debug = DEBUG
+    app.secret_key = SECRET_KEY
+
+You no longer have to do that, instead you can just load a configuration
+into the config object.  How this works is outlined in :ref:`config`.
+
+Logging Integration
+```````````````````
+
+Flask now configures a logger for you with some basic and useful defaults.
+If you run your application in production and want to profit from
+automatic error logging, you might be interested in attaching a proper log
+handler.  Also you can start logging warnings and errors into the logger
+when appropriately.  For more information on that, read
+:ref:`application-errors`.
+
+Categories for Flash Messages
+`````````````````````````````
+
+Flash messages can now have categories attached.  This makes it possible
+to render errors, warnings or regular messages differently for example.
+This is an opt-in feature because it requires some rethinking in the code.
+
+Read all about that in the :ref:`message-flashing-pattern` pattern.