Add Machine Learning: PredictionIO Ruby SDK.
Merge pull request #99 from Erol/predictionio-ruby-sdk

Add Machine Learning: PredictionIO Ruby SDK.
add Machine Learning section to menu
Add Machine Learning: Ruby Datumbox Wrapper.
Merge pull request #100 from brunosoab/master

Add Machine Learning: Ruby Datumbox Wrapper.
Added: mobile development to TOC
Added: Category: Money and money gem
Merge pull request #101 from torokmark/master

Added: mobile development to TOC
Added: Category: Ebook
Added: gepub gem
Added: git-scribe gem
Added: review gem
Added: eeepub gem
Moved: prawn gem under Ebook category
Added: pdfkit gem
Added: Wicket pdf gem
Added: kitabu gem
Added: gimli gem
Added: shrimp gem
Added: rghost gem