diff --git a/Dockerfile b/Dockerfile
index 92be2ee..d1994bd 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,3 +1,11 @@
-FROM ruby:2.1.9-onbuild
+FROM ruby:2.1.9-alpine
+
+LABEL maintainer "Knut Ahlers <knut@ahlers.me>"
+
+COPY . /src
+WORKDIR /src
+
+RUN set -ex \
+ && bundle install --full-index
 
 ENTRYPOINT ["./watch.rb"]