diff --git a/Gemfile b/Gemfile
index c188665..35bb4a9 100644
--- a/Gemfile
+++ b/Gemfile
@@ -4,6 +4,8 @@ source 'https://rubygems.org'
 
 gem 'tox', path: '../tox.rb'
 
+gem 'curses', '~> 1.2'
+
 group :development, :test do
   gem 'rubocop', '~> 0.49.1'
 end
diff --git a/Gemfile.lock b/Gemfile.lock
index 11ac78a..5b3da89 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -7,6 +7,7 @@ GEM
   remote: https://rubygems.org/
   specs:
     ast (2.3.0)
+    curses (1.2.3)
     parallel (1.11.2)
     parser (2.4.0.0)
       ast (~> 2.2)
@@ -28,6 +29,7 @@ PLATFORMS
   ruby
 
 DEPENDENCIES
+  curses (~> 1.2)
   rubocop (~> 0.49.1)
   tox!