[DOC] report.

bzr revid: vmt@openerp.com-20130222153649-h4quh4r8ptz465s1

doc/03_module_dev.rst

@@ -13,3 +13,4 @@ Modules
    03_module_dev_04
    03_module_dev_05
    03_module_dev_06
+   report-declaration

doc/report-declaration.rst

@@ -0,0 +1,23 @@
+.. _report-declaration:
+
+Report declaration
+==================
+
+.. versionadded:: 7.1
+
+Before version 7.1, report declaration could be done in two different ways:
+either via a ``<report>`` tag in XML, or via such a tag and a class
+instanciation in a Python module. Instanciating a class in a Python module was
+necessary when a custom parser was used.
+
+In version 7.1, the recommended way to register a report is to use only the
+``<report>`` XML tag. The tag can now support an additional ``parser``
+attribute. The value for that attibute must be a fully-qualified class name,
+without the leading ``openerp.addons.`` namespace.
+
+.. note::
+  The rational to deprecate the manual class instanciation is to make all
+  reports visible in the database, have a unique way to declare reports
+  instead of two, and remove the need to maintain a registry of reports in
+  memory.
+