diff --git a/Dockerfile b/Dockerfile
index c269b83..9c2eb5e 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -13,6 +13,7 @@ RUN wget http://kindlegen.s3.amazonaws.com/${KINDLEGEN} && \
     tar zxf ${KINDLEGEN} -C /opt/kindlegen && \
     rm ${KINDLEGEN}
 
+COPY narou-3.1.1.gem .
 RUN gem install narou -v ${NAROU_VERSION} --no-document
 
 COPY init.sh /usr/local/bin
diff --git a/narou-3.1.1.gem b/narou-3.1.1.gem
new file mode 100644
index 0000000..3ed15a9
Binary files /dev/null and b/narou-3.1.1.gem differ