diff --git a/scripts/Gemfile b/scripts/Gemfile
new file mode 100644
index 0000000000..22a63fb45d
--- /dev/null
+++ b/scripts/Gemfile
@@ -0,0 +1,3 @@
+source "https://rubygems.org"
+
+gem 'git', '~> 2.3'
diff --git a/scripts/committers.rb b/scripts/committers.rb
index 87f8ec9b60..9d6573ce2e 100755
--- a/scripts/committers.rb
+++ b/scripts/committers.rb
@@ -1,4 +1,6 @@
-#!/usr/bin/ruby
+#!/usr/bin/env ruby
+# Run with: bundle exec --gemfile=scripts/Gemfile ruby ./committers.rb TAG_FROM TAG_TO
+# Or from scripts directory: bundle exec ./committers.rb TAG_FROM TAG_TO
 require 'tmpdir'
 require 'git'
 require 'optparse'