diff --git a/2019/ruby/Gemfile b/2019/ruby/Gemfile
new file mode 100644
index 0000000..e03b97c
--- /dev/null
+++ b/2019/ruby/Gemfile
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+source "https://rubygems.org"
+
+git_source(:github) {|repo_name| "https://github.com/#{repo_name}" }
+
+gem "minitest"
diff --git a/2019/ruby/Gemfile.lock b/2019/ruby/Gemfile.lock
new file mode 100644
index 0000000..5846597
--- /dev/null
+++ b/2019/ruby/Gemfile.lock
@@ -0,0 +1,13 @@
+GEM
+  remote: https://rubygems.org/
+  specs:
+    minitest (5.13.0)
+
+PLATFORMS
+  ruby
+
+DEPENDENCIES
+  minitest
+
+BUNDLED WITH
+   2.0.2
diff --git a/2019/ruby/day_01.rb b/2019/ruby/day_01.rb
new file mode 100644
index 0000000..c766399
--- /dev/null
+++ b/2019/ruby/day_01.rb
@@ -0,0 +1,15 @@
+# puts ARGF.read.lines.map(&:to_i).map {|mass|
+#   (mass / 3.0).floor - 2
+# }.sum
+
+fuel = ->(mass) {
+  total = 0
+  loop do
+    mass = (mass / 3.0).floor - 2
+    break if mass <= 0
+    total += mass
+  end
+  total
+}
+
+puts ARGF.read.lines.map(&:to_i).map(&fuel).sum