Gemfile when developing between two platforms - ruby

Question

I am carrying out some development of a Ruby on Rails app between a Windows machine and linux machine. Not ideal but Ruby on Windows has improved a lot. Anyway i read that you can implement an IF statement so for example I have implemented this
source 'https://rubygems.org'
if RUBY_PLATFORM =~ /win32/
gem 'rails', '3.2.3'
gem 'sqlite3'
group :assets do
gem 'sass-rails', '~> 3.2.3'
gem 'coffee-rails', '~> 3.2.1'
gem 'twitter-bootstrap-rails', :git => 'git://github.com/seyhunak/twitter-bootstrap-rails.git'
gem 'uglifier', '>= 1.0.3'
end
gem 'jquery-rails'
gem 'nokogiri'
gem 'httparty'
gem 'devise'
else
gem 'rails', '3.2.3'
gem 'sqlite3', '1.3.6'
group :assets do
gem 'sass-rails', '~> 3.2.3'
gem 'coffee-rails', '~> 3.2.1'
gem 'twitter-bootstrap-rails', :git => 'git://github.com/seyhunak/twitter-bootstrap-rails.git'
gem 'less-rails'
gem 'uglifier', '>= 1.0.3'
gem 'execjs'
gem 'therubyracer', '0.10.2'
end
gem 'jquery-rails'
gem 'nokogiri'
gem 'httparty'
gem 'devise'
end
So this morning I merged my linux branch into the master branch (windows) and now i get the message
Could not find the less-rails in any of the sources
So it seems as if the IF statement has not worked or there is an issue with my bootstrap.css.less file in assets as I use this in my linux branch
How can i get this to work, so either have less working on both platforms or get windows to ignore the less gem
has anyone got around this before
UPDATE
Ok so i have found that if I specify
:platform => :ruby
after the less-rails gem it ignores it (though I had to add to execjs and rubyracer aswell) due to js runtime conflicts.. So question still remains as to what is wrong with my IF/ELSE statement
Thanks

Answer 1

Have you rebuilt the bundle lock file?
Try this on your Windows machine:
bundle install
bundle update
To learn about bundle, Gemfile, Gemfile.lock, and why you need to rebuild the lock when you switch platforms: http://gembundler.com/rationale.html