1 files changed, 1 insertions, 0 deletions
diff --git a/Gemfile b/Gemfile
index 6af27ce0f3e..38158387642 100644
--- a/Gemfile
+++ b/Gemfile
@@ -327,6 +327,7 @@ group :test do
   gem 'test_after_commit', '~> 1.1'
   gem 'sham_rack', '~> 1.3.6'
   gem 'timecop', '~> 0.8.0'
+  gem 'concurrent-ruby', '~> 1.0.5'
 end
 
 gem 'octokit', '~> 4.6.2'