add ruby library
Update Ruby docs [ci skip]
Remove unnecessary Ruby files

The tasks provided by Bundler conflict with our build and release
process, and provide no extra value. Additionally, the gem has no
external dependencies, so there's no need to maintain a Gemfile for it.
add ruby package and release tasks
Bump Ruby gem to 0.1.1

0.1.0 was accidentally pushed, then yanked, so it can't be used again as
a version number.