Built ruby demo

Contains a simple todo app built in Ruby, with an accompanying README.
Added a Gemfile
Changed datastore credentials example to be more standard
Added HTTP logger to examine requests
Changed key names and commented out logger by default. Also removedand ignored Gemfile.lock
Added ancestor query and insertion to make sure quries always returned strongly consistent results
Removed Gemfile lock
Update readme and commented out request logger
Fixed ID display after post
Fixed ID display after post
Merge branch 'added_ruby_demo' of https://github.com/sudhirj/google-cloud-datastore into added_ruby_demo
Added license message
update todo creation message
commented header back