Add python-dev to Dockerfile
diff --git a/Dockerfile b/Dockerfile
index a3a2060..f10d7bd 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -26,6 +26,7 @@
 
 RUN apt-get update
 RUN apt-get install -y python
+RUN apt-get install -y python-dev
 RUN apt-get install -y python-pip
 RUN apt-get clean all