Only include lib and doc files in gem

Author: Jon Elverkilde

pusher.gemspec

@@ -29,8 +29,6 @@ Gem::Specification.new do |s|
   s.add_development_dependency "json", "~> 2.3"
   s.add_development_dependency "rbnacl", "~> 7.1"
 
-  s.files         = `git ls-files`.split("\n")
-  s.test_files    = `git ls-files -- {test,spec,features}/*`.split("\n")
-  s.executables   = `git ls-files -- bin/*`.split("\n").map{ |f| File.basename(f) }
+  s.files         = Dir["lib/**/*"] + %w[CHANGELOG.md LICENSE README.md]
   s.require_paths = ["lib"]
 end