Require rainbow gem version to be 2.1.x due to ku1ik/rainbow#40 (#516)

tommyschaefer · kotp · commit 11ac0bb4a457 · 2016-12-27T23:52:28.000-05:00
diff --git a/Gemfile b/Gemfile
@@ -1,6 +1,7 @@
 source 'https://rubygems.org'
 
 gem 'minitest'
+gem 'rainbow', '>= 2.1.0', '< 2.2.0'
 gem 'rubocop', '0.36.0'
 gem 'simplecov'
 gem 'rake'
