diff --git a/commit-watcher/Dockerfile b/commit-watcher/Dockerfile
index 6d3be97..008e103 100644
--- a/commit-watcher/Dockerfile
+++ b/commit-watcher/Dockerfile
@@ -19,6 +19,7 @@ RUN	set -x \
 	&& cd /usr/src/commit-watcher \
 	&& bundle config build.nokogiri --use-system-libraries \
 	&& bundle install \
+	&& gem install activesupport --no-rdoc --no-ri \
 	&& apk del .build-deps
 
 WORKDIR /usr/src/commit-watcher