diff --git a/Dockerfile b/Dockerfile
index b1cc2eb1397e1d7fb2d1aa09c471bd18b9e1457c..4a6afad7817a0cea8c5b88951bae59187db913e1 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -4,7 +4,8 @@ RUN umask 0044
 
 RUN mkdir -p /reveal_js
 
-COPY package*.json external Gruntfile.js /reveal_js/
+COPY package*.json Gruntfile.js /reveal_js/
+COPY external /reveal_js/external/
 
 WORKDIR /reveal_js