As the title suggests! Here are the relevant files/configs:
$ gem list --local
*** LOCAL GEMS ***
Ascii85 (1.0.2)
bcrypt-ruby (3.0.1)
hashery (2.0.1)
pdf-reader (1.2.0)
prawn (0.12.0)
ruby-rc4 (0.1.5)
ttfunk (1.0.3)
$ grep bcrypt Gemfile
gem 'bcrypt-ruby', '~> 3.0.0'
$ grep bcrypt Gemfile.lock
bcrypt-ruby (3.0.1)
bcrypt-ruby
Any "require bcrypt" causes the error. I've run bundle install.