diff --git a/Gemfile.lock b/Gemfile.lock
index e9178f1..161485f 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -16,6 +16,7 @@ PATH
       kramdown-haml
       puma
       rails (= 4.1.4)
+      rubyzip
       sass-rails (~> 4.0.3)
       settingslogic
       sucker_punch (~> 1.0.5)
@@ -175,6 +176,7 @@ GEM
       rspec-core (~> 2.99.0)
       rspec-expectations (~> 2.99.0)
       rspec-mocks (~> 2.99.0)
+    rubyzip (1.1.6)
     safe_yaml (1.0.3)
     sass (3.2.19)
     sass-rails (4.0.3)
diff --git a/fluentd-ui.gemspec b/fluentd-ui.gemspec
index dcd6999..9961e7f 100644
--- a/fluentd-ui.gemspec
+++ b/fluentd-ui.gemspec
@@ -36,4 +36,5 @@ Gem::Specification.new do |spec|
   spec.add_dependency "thor"
   spec.add_dependency "kramdown", "> 1.0.0"
   spec.add_dependency "kramdown-haml"
+  spec.add_dependency "rubyzip"
 end