diff --git a/CHANGELOG.md b/CHANGELOG.md
index 56e4912..69375eb 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,8 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 
 **Gem enhancements:**
 
+- Reduced production gem size by 9 times [[#345](https://github.com/panorama-ed/memo_wise/pull/345)]
+
 _No breaking changes!_
 
 **Project enhancements:**
diff --git a/memo_wise.gemspec b/memo_wise.gemspec
index 6c951a6..412c22c 100644
--- a/memo_wise.gemspec
+++ b/memo_wise.gemspec
@@ -26,13 +26,7 @@ Gem::Specification.new do |spec|
   spec.required_ruby_version = Gem::Requirement.new(">= 2.5.0")
 
   # Specify which files should be added to the gem when it is released.
-  # The `git ls-files -z` loads the files in the RubyGem that have been added
-  # into git.
-  spec.files = Dir.chdir(File.expand_path(__dir__)) do
-    `git ls-files -z`.split("\x0").reject do |f|
-      f.match(%r{^(test|spec|features)/})
-    end
-  end
+  spec.files = Dir.glob("{CHANGELOG.md,LICENSE.txt,README.md,lib/**/*.rb}")
   spec.require_paths = ["lib"]
 
   spec.metadata = {