This is also a requirement
diff --git a/dev-requirements.txt b/dev-requirements.txt
index b2a6c79..70a2b9b 100644
--- a/dev-requirements.txt
+++ b/dev-requirements.txt
@@ -5,6 +5,7 @@
 pretend
 pytest
 sphinx
+sphinxcontrib-spelling
 sphinx_rtd_theme
 tox
 twine