diff --git a/.dockerignore b/.dockerignore
new file mode 100644
index 0000000..4d2be69
--- /dev/null
+++ b/.dockerignore
@@ -0,0 +1,23 @@
+/.bundle/
+/.yardoc
+/_yardoc/
+/coverage/
+/doc/
+/pkg/
+/spec/reports/
+/tmp/
+
+*.bundle
+*.so
+*.o
+*.a
+mkmf.log
+
+# rspec failure tracking
+.rspec_status
+
+# Added by cargo
+/target
+
+# Built gems
+*.gem
diff --git a/docker/Dockerfile b/docker/Dockerfile
index fa16089..a449a1d 100644
--- a/docker/Dockerfile
+++ b/docker/Dockerfile
@@ -1,8 +1,17 @@
 FROM ruby:3.2.3
 WORKDIR /app
+
+# Install the requirements we need to build the native Rust extensions
 RUN apt-get update -qq && \
     apt-get upgrade -y && \
     apt-get install -y libclang-dev
-COPY Gemfile /app
+
+# Package and install the gem
+COPY . /app
+RUN gem build tzf.gemspec
+RUN gem install tzf-*.gem
+
+# Run a sanity check
+WORKDIR /app/docker
 RUN bundle install
-CMD echo 'Hello, world!'
+CMD ruby sanity_check.rb
diff --git a/docker/Gemfile b/docker/Gemfile
index 28e74ad..13135d2 100644
--- a/docker/Gemfile
+++ b/docker/Gemfile
@@ -2,4 +2,4 @@ source "https://rubygems.org"
 
 # gem "rb_sys", "0.9.87"
 
-gem "tzf", git: "https://github.com/HarlemSquirrel/tzf-rb", branch: "bundle-update-20240219"
+gem "tzf"
diff --git a/docker/sanity_check.rb b/docker/sanity_check.rb
new file mode 100644
index 0000000..43df53b
--- /dev/null
+++ b/docker/sanity_check.rb
@@ -0,0 +1,5 @@
+require "bundler/setup"
+require "tzf"
+
+puts TZF::VERSION
+puts TZF.tz_name(40.74771675713742, -73.99350390136448)