(PDOC-78) Include LICENSE, docs and specs in gem

puppet-strings.gemspec

@@ -7,7 +7,15 @@ Gem::Specification.new do |s|
   s.email = 'info@puppetlabs.com'
   s.homepage = 'https://github.com/puppetlabs/puppetlabs-strings'
   s.description = s.summary
-  s.files = Dir['lib/**/*'].reject { |f| f if File.directory?(f) }
+
+  s.extra_rdoc_files = [
+    'CHANGELOG.md',
+    'COMMITTERS.md',
+    'CONTRIBUTING.md',
+    'LICENSE',
+    'README.md',
+  ]
+  s.files = `git ls-files`.split("\n") - Dir['.*', '*.gemspec']
 
   s.add_runtime_dependency 'puppet', '>= 3.7.0'
   s.add_runtime_dependency 'yard', '~> 0.8'