This project rocks and uses MIT-LICENSE.
Add this line to your Gemfile:
gem "dashify_rails", git: 'https://github.com/bmxpert1/dashify_rails', require: ['dashify_rails', 'websocket-rails']
Please note that NVD3 is provided via the asset pipeline and you do not need to copy their files into your application. Rails will get them from dashify-rails automatically.
Then add it to your javascript manifest file, most probably at app/assets/javascripts/application.js:
//= require dashify_rails
Then add it to your css manifest file, most probably at app/assets/stylesheets/application.css:
*= require dashify_rails