Set version to 5.0.1

docs/releases.rst

@@ -4,6 +4,7 @@ Release notes
 .. toctree::
    :maxdepth: 2
 
+   releases/v5.0.1
    releases/v5.0.0
    releases/v4.5.3
    releases/v4.5.2

docs/releases/v5.0.1.rst

+What's new in Tornado 5.0.1
+===========================
+
+Mar 18, 2018
+------------
+
+Bug fix
+~~~~~~~
+
+- This release restores support for versions of Python 3.4 prior to
+  3.4.4. This is important for compatibility with Debian Jessie which
+  has 3.4.2 as its version of Python 3.

setup.py

@@ -103,7 +103,7 @@ http://api.mongodb.org/python/current/installation.html#osx
 
 kwargs = {}
 
-version = "5.0"
+version = "5.0.1"
 
 with open('README.rst') as f:
     kwargs['long_description'] = f.read()

tornado/__init__.py

@@ -24,5 +24,5 @@ from __future__ import absolute_import, division, print_function
 # is zero for an official release, positive for a development branch,
 # or negative for a release candidate or beta (after the base version
 # number has been incremented)
-version = "5.0"
-version_info = (5, 0, 0, 0)
+version = "5.0.1"
+version_info = (5, 0, 1, 0)