diff --git a/Dockerfile b/Dockerfile
index 11063b6..49b1d6e 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -18,7 +18,7 @@ WORKDIR /app
 # will be cached unless changes to one of those two files
 # are made.
 COPY Gemfile Gemfile.lock ./
-RUN gem install bundler && bundle install --jobs 20 --retry 5
+RUN gem install bundler -v 1.11.2 && bundle install --jobs 20 --retry 5
 
 # Copy the main application.
 COPY . ./