diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..b844b14
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+Gemfile.lock
diff --git a/Dockerfile b/Dockerfile
index fc14e49..8123674 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -9,4 +9,9 @@ RUN useradd -u 1000 gnuplot; \
 WORKDIR /home/gnuplot/gnuplot
 
 USER gnuplot
-RUN gem install jeweler2
+
+COPY lib/ ./lib/
+COPY *.gemspec ./
+COPY Gemfile ./
+
+RUN gem install bundler; bundle install