kruger@kruger:~/.subbot$ bundle install --path vendor/bundle
Fetching gem metadata from https://rubygems.org/.......
Resolving dependencies...
Installing i18n 0.6.5
Installing minitest 4.7.5
Installing multi_json 1.8.2

Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension.

        /usr/bin/ruby1.9.1 extconf.rb
/usr/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require': cannot load such file -- mkmf (LoadError)
        from /usr/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require'
        from extconf.rb:13:in `<main>'


Gem files will remain installed in /home/kruger/.subbot/vendor/bundle/ruby/1.9.1/gems/atomic-1.1.14 for inspection.
Results logged to /home/kruger/.subbot/vendor/bundle/ruby/1.9.1/gems/atomic-1.1.14/ext/gem_make.out
An error occurred while installing atomic (1.1.14), and Bundler cannot
continue.
Make sure that `gem install atomic -v '1.1.14'` succeeds before bundling.
kruger@kruger:~/.subbot$