Add Deprecation Roadmap to backward compatibility document

We should replace the wiki document to a link to this document now

doc/en/backwards-compatibility.rst

@@ -10,3 +10,67 @@ With the pytest 3.0 release we introduced a clear communication scheme for when
 To communicate changes we are already issuing deprecation warnings, but they are not displayed by default. In pytest 3.0 we changed the default setting so that pytest deprecation warnings are displayed if not explicitly silenced (with ``--disable-pytest-warnings``).
 
 We will only remove deprecated functionality in major releases (e.g. if we deprecate something in 3.0 we will remove it in 4.0), and keep it around for at least two minor releases (e.g. if we deprecate something in 3.9 and 4.0 is the next release, we will not remove it in 4.0 but in 5.0).
+
+
+Deprecation Roadmap
+-------------------
+
+This page lists deprecated features and when we plan to remove them. It is important to list the feature, the version where it got deprecated and the version we plan to remove it.
+
+Following our deprecation policy, we should aim to keep features for *at least* two minor versions after it was considered deprecated.
+
+3.4
+~~~
+
+**Old style classes**
+
+Issue: `#2147 <https://github.com/pytest-dev/pytest/issues/2147>`_.
+
+Deprecated in ``3.2``.
+
+4.0
+~~~
+
+**Yield tests**
+
+Deprecated in ``3.0``.
+
+**pytest-namespace hook**
+
+deprecated in ``3.2``.
+
+**Marks in parameter sets**
+
+Deprecated in ``3.2``.
+
+**--result-log**
+
+Deprecated in ``3.0``.
+
+See `#830 <https://github.com/pytest-dev/pytest/issues/830>`_ for more information. Suggested alternative: `pytest-tap <https://pypi.python.org/pypi/pytest-tap>`_.
+
+**metafunc.addcall**
+
+Issue: `#2876 <https://github.com/pytest-dev/pytest/issues/2876>`_.
+
+Deprecated in ``3.3``.
+
+**pytest_plugins in non-toplevel conftests**
+
+There is a deep conceptual confusion as ``conftest.py`` files themselves are activated/deactivated based on path, but the plugins they depend on aren't.
+
+Issue: `#2639 <https://github.com/pytest-dev/pytest/issues/2639>`_.
+
+Not yet officially deprecated.
+
+**passing a single string to pytest.main()**
+
+Pass a list of strings to ``pytest.main()`` instead.
+
+Deprecated in ``3.1``.
+
+**[pytest] section in setup.cfg**
+
+Use ``[tool:pytest]`` instead for compatibility with other tools.
+
+Deprecated in ``3.0``.