I got this really annoying error “bcrypt-ruby – You don’t have bcrypt-ruby installed in your application” when I was trying to use blowfish secure password on my rails application. After few hours finding the solution, I finally have it fixed. I use Ruby 2.0 and Rails 4.0.0 and below is how to solve this issue:
1) Uninstall any previous version of bcrypt you have on your system. Go to command line, on the root of your application, type this:
gem uninstall bcrypt
2) Update Rails version to 4.0.1 and install bcrypt version 3.1.2. To do this, open your Gemfile from the root of your application, and change the info there into this:
gem 'rails', '4.0.1'
gem 'bcrypt-ruby', '~> 3.1.2'