diff --git a/Dockerfile b/Dockerfile
index fed36db..fad65f2 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -3,7 +3,7 @@ FROM python:alpine
 ADD requirements.txt /
 ADD hugo-encryptor.py /
 
-RUN apk add --update libxslt-dev libxml2-dev gcc && \
+RUN apk add --update libxslt-dev libxml2-dev gcc musl-dev && \
     rm -rf /var/cache/apk/*
 
 RUN pip install --no-cache-dir -r /requirements.txt