Bundler could not find compatible versions for gem “railties” for Rails 4.0.0

Question

I am trying to upgrade to Rails 4.0.0, and I changed the gem versions of sass-rails and coffee-rails. I need to resolve this gem conflict between <

Answer 1

1. Delete the Gemfile.lock file
2. refer here for basic gemfile changes
3. run bundle install

Everything will work fine. :)