Debian builds packages from source tarballs so git cannot find list of files

--- a/rqrcode.gemspec
+++ b/rqrcode.gemspec
@@ -20,9 +20,7 @@
   spec.homepage      = "https://github.com/whomwah/rqrcode"
   spec.license       = "MIT"
 
-  spec.files         = Dir.chdir(File.expand_path('..', __FILE__)) do
-    `git ls-files -z`.split("\x0").reject { |f| f.match(%r{^(test|spec|features)/}) }
-  end
+  all_files = Dir.glob("**/*").select {|v| v !~ /^(test|spec|features|debian)/}
   spec.bindir        = "exe"
   spec.executables   = spec.files.grep(%r{^exe/}) { |f| File.basename(f) }
   spec.require_paths = ["lib"]