diff --git a/requirements.txt b/requirements.txt
index 13a589c..8e744fc 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -16,6 +16,7 @@ Flask-Script==2.0.6
 Flask-Security-Too==3.4.2
 Flask-SQLAlchemy==2.4.3
 Flask-WTF==0.14.3
+gunicorn==20.0.4
 idna==2.9
 itsdangerous==1.1.0
 Jinja2==2.11.2