Add small section on migrating from nose to pytest

The section currently features the nose2pytest tool with plans to expand
on some of the common gotchas when performing such migrations.

Author: mickeypash

AUTHORS

@@ -200,6 +200,7 @@ Matthias Hafner
 Maxim Filipenko
 Maximilian Cosmo Sitter
 mbyt
+Mickey Pashov
 Michael Aquilina
 Michael Birtwell
 Michael Droettboom

doc/en/nose.rst

@@ -68,4 +68,13 @@ Unsupported idioms / known issues
   fundamentally incompatible with pytest because they don't support fixtures
   properly since collection and test execution are separated.
 
+Migrating from Nose to Pytest
+------------------------------
+
+`nose2pytest <https://github.com/pytest-dev/nose2pytest>`_ is a Python script
+and py.test plugin to help convert Nose-based tests into py.test-based tests.
+Specifically, the script transforms nose.tools.assert_* function calls into
+raw assert statements, while preserving format of original arguments
+as much as possible.
+
 .. _nose: https://nose.readthedocs.io/en/latest/