add Gemfile

.gitignore

-*.sw?
+*.a
+/.bundle/
+*.bundle
+/coverage/
+/doc/
 .DS_Store
-coverage
+/Gemfile.lock
+ipaddr.html
+mkmf.log
+*.o
+/pkg/
 rdoc
-pkg
 server.rb
-ipaddr.html
+*.so
+/spec/reports/
+*.sw?
+/tmp/
+/_yardoc/

Gemfile

+source "https://rubygems.org"
+
+gemspec