diff --git a/Gemfile b/Gemfile
index 30cf7fb..a6cb09f 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,5 +1,7 @@
 source 'https://rubygems.org'
 
+gem "tzinfo-data"
+
 # for working locally
 # gem "sassc", :path => "../sassc"