diff --git a/Dockerfile b/Dockerfile
index 446bba7..1955693 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -4,5 +4,6 @@ RUN mkdir /myapp
 WORKDIR /myapp
 ADD Gemfile /myapp/Gemfile
 ADD Gemfile.lock /myapp/Gemfile.lock
+RUN gem install bundler -v 1.17.3
 RUN bundle install
 ADD . /myapp
diff --git a/Gemfile.lock b/Gemfile.lock
index 1f0b562..16e1c4f 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -182,7 +182,9 @@ GEM
     marcel (0.3.3)
       mimemagic (~> 0.3.2)
     method_source (0.9.2)
-    mimemagic (0.3.3)
+    mimemagic (0.3.9)
+      nokogiri (~> 1)
+      rake
     mini_mime (1.0.2)
     mini_portile2 (2.4.0)
     minitest (5.13.0)