diff --git a/diversipub.gemspec b/diversipub.gemspec
index d67f4e1..09409d4 100644
--- a/diversipub.gemspec
+++ b/diversipub.gemspec
@@ -43,6 +43,7 @@ Gem::Specification.new do |spec|
 
   spec.executables = spec.files.grep(%r{\Aexe/}) { |f| File.basename f }
 
+  spec.add_runtime_dependency 'erb',             '~> 4.0', '>= 4.0.2'
   spec.add_runtime_dependency 'json',            '~> 2.6', '>= 2.6.3'
   spec.add_runtime_dependency 'puma',            '~> 6.2', '>= 6.2.2'
   spec.add_runtime_dependency 'rack',            '~> 2.2', '>= 2.2.7'
diff --git a/lib/diversipub.rb b/lib/diversipub.rb
index 6743fb5..963c749 100644
--- a/lib/diversipub.rb
+++ b/lib/diversipub.rb
@@ -11,6 +11,7 @@ require 'pathname'
 # Gems #
 ########
 
+require 'erb'
 require 'json'
 require 'puma'
 require 'rack'