diff --git a/Gemfile b/Gemfile
index ebc4588..e192541 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,3 +1,5 @@
 # frozen_string_literal: true
 
 source 'https://rubygems.org'
+
+gem 'tox', path: '../tox.rb'
diff --git a/Gemfile.lock b/Gemfile.lock
index 2b95539..189e953 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,3 +1,8 @@
+PATH
+  remote: ../tox.rb
+  specs:
+    tox (0.0.1)
+
 GEM
   remote: https://rubygems.org/
   specs:
@@ -6,6 +11,7 @@ PLATFORMS
   ruby
 
 DEPENDENCIES
+  tox!
 
 BUNDLED WITH
    1.13.6