diff --git a/Gemfile.lock b/Gemfile.lock
index 098e433..bfde06c 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -87,8 +87,9 @@ GEM
     psych (5.1.2)
       stringio
     racc (1.8.1)
-    rack (3.1.8)
-    rack-session (2.0.0)
+    rack (3.1.14)
+    rack-session (2.1.1)
+      base64 (>= 0.1.0)
       rack (>= 3.0.0)
     rack-test (2.1.0)
       rack (>= 1.3)
diff --git a/gemfiles/Gemfile-rails-6-0 b/gemfiles/Gemfile-rails-6-0
index 49909b4..7f7e8da 100644
--- a/gemfiles/Gemfile-rails-6-0
+++ b/gemfiles/Gemfile-rails-6-0
@@ -10,6 +10,8 @@ gem "rake-compiler"
 gem "minitest"
 gem "mocha"
 gem "ruby_memcheck"
+gem "logger", "~> 1.6"
+gem "mutex_m", "~> 0.3"
 
 group :deployment, :test do
   gem "pry-byebug"
diff --git a/gemfiles/Gemfile-rails-6-1 b/gemfiles/Gemfile-rails-6-1
index 179bd88..83dcbcc 100644
--- a/gemfiles/Gemfile-rails-6-1
+++ b/gemfiles/Gemfile-rails-6-1
@@ -10,6 +10,8 @@ gem "rake-compiler"
 gem "minitest"
 gem "mocha"
 gem "ruby_memcheck"
+gem "logger", "~> 1.6"
+gem "mutex_m", "~> 0.3"
 
 group :deployment, :test do
   gem "pry-byebug"
diff --git a/lib/better_html.rb b/lib/better_html.rb
index 0725fc3..a088a8a 100644
--- a/lib/better_html.rb
+++ b/lib/better_html.rb
@@ -1,5 +1,6 @@
 # frozen_string_literal: true
 
+require "logger"
 require "active_support/core_ext/hash/keys"
 require "active_support/core_ext/module/delegation"
 require "active_support/core_ext/class/attribute_accessors"
diff --git a/test/test_helper.rb b/test/test_helper.rb
index cdccdd9..dbec6a1 100644
--- a/test/test_helper.rb
+++ b/test/test_helper.rb
@@ -1,5 +1,6 @@
 # frozen_string_literal: true
 
+require "logger"
 require "active_support"
 require "minitest/autorun"
 require "better_html"