diff --git a/dockercoins/hasher/Dockerfile b/dockercoins/hasher/Dockerfile
index 1c5e264f..5e2e9ee0 100644
--- a/dockercoins/hasher/Dockerfile
+++ b/dockercoins/hasher/Dockerfile
@@ -1,5 +1,6 @@
 FROM ruby
 RUN gem install sinatra
+RUN gem install thin
 ADD hasher.rb /
 CMD ["ruby", "hasher.rb"]
 EXPOSE 80