diff --git a/app.rb b/app.rb
index 33c1c74..dd4ed0f 100644
--- a/app.rb
+++ b/app.rb
@@ -5,6 +5,7 @@ require "sinatra/multi_route"
 require "time"
 require "fileutils"
 require "json"
+require "singleton"
 
 require "securerandom"
 require "random/formatter"