This setup guide will not pollute your system gem library and will use the local copy of the openconferenceware engine.
Fork the repo from https://github.com/osbridge/openconferenceware
$ git clone git@github.com:username/openconferenceware.git
$ mkdir myconf
$ cd myconf
$ vi Gemfile
source 'https://rubygems.org'
gem 'rails' , '4.0.2'
$ bundle install --path gems --binstubs=gembin
$ gembin/rails new web --skip-bundle
$ cd web
$ vi Gemfile
** Add this line
gem 'open_conference_ware', :git => "../../openconferenceware"
$ bundle install --path gems
$ bin/rails s