diff --git a/MANIFEST.in b/MANIFEST.in
index 765ff49f..739fef39 100644
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -6,3 +6,4 @@ recursive-exclude * __pycache__
 recursive-exclude * *.py[co]
 
 recursive-include *.rst Makefile *.jpg *.png *.gif
+include requirements/constraints.txt
diff --git a/setup.py b/setup.py
index 3702579d..7991d807 100644
--- a/setup.py
+++ b/setup.py
@@ -1,7 +1,9 @@
+import os
+import re
 from glob import glob
 from os.path import basename, splitext
 
-from setuptools import setup, find_packages
+from setuptools import find_packages, setup
 
 with open("README.rst") as readme_file:
     readme = readme_file.read()