Demonstrate bundler following symlinks

Gemfile

# /tmp/foo/Gemfile

source 'https://rubygems.org'
gem 'rake'
gem 'unicorn'

gistfile1.txt

$ cd /tmp
$ ln -s foo bar
$ cd /tmp/foo
$ bundle install --path gems
$ bundle exec rake foo
##### /tmp/foo/gems/ruby/1.9.1/gems/unicorn-4.3.1/bin/unicorn_rails
$ cd ../bar
$ bundle exec rake foo
##### /tmp/foo/gems/ruby/1.9.1/gems/unicorn-4.3.1/bin/unicorn_rails

lib_tasks_foo.rb

# /tmp/foo/Rakefile

task :foo do
  $stderr.puts '##### ' + Gem.bin_path('unicorn', 'unicorn_rails', '>= 0')
end