diff --git a/Dockerfile b/Dockerfile
index 167dd11..b5cae9d 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,11 +1,15 @@
 FROM ruby:3.4.3-alpine
 USER root
 WORKDIR /build
-COPY . /build
+
+COPY Gemfile /build/
+COPY *.gemspec /build/
 
 RUN gem update \
-    && gem install concurrent-ruby \
+    && bundle config set jobs $(nproc) \
     && bundle install
 
+COPY . /build
+
 WORKDIR /
 ENTRYPOINT [ "/build/bin/wayback_machine_downloader" ]
\ No newline at end of file