Add some tags to optimize for zenback

For more detail about tags, refer to the following article.

http://nanapi.jp/29761/
Merge pull request #49 from satoryu/feature/optimize_for_zenback

zenbackの関連度合いを向上させるタグを挿入する
update dependency: rspec-2.13.0
added rubykaigi 2013
Merge branch 'master', remote-tracking branch 'official/master'