Fix file selection for gem

build/ruby/tucana.gemspec

@@ -18,14 +18,7 @@ Gem::Specification.new do |spec|
   spec.metadata["changelog_uri"] = "#{spec.homepage}/releases"
 
   # 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(__dir__) do
-    `git ls-files -z`.split("\x0").reject do |f|
-      (File.expand_path(f) == __FILE__) || f.start_with?(*%w[bin/ spec/ .git .github])
-    end
-  end
-  spec.bindir = "exe"
-  spec.executables = spec.files.grep(%r{\Aexe/}) { |f| File.basename(f) }
+  spec.files = Dir["lib/**/*.rb"]
   spec.require_paths = ["lib"]
 
   # Uncomment to register a new dependency of your gem