Add Gemfile, pointing to RubyGems & our internal Gemfury

@djhartman, ping me for instructions on how to use Gemfury to
publish gems internally
Add Bundler, Rake, & Fury as dev gems to Gemspec

Ensures we have all the tools we need to build & ship a release
Bump to v1.0.0, as this is used in production

Production gems should have proper versions, and adhere to SemVer.

See http://semver.org for details (@djhartman)