/usr/local/lib/ruby/site_ruby/2.1.0/rubygems/core_ext/kernel_require.rb:54:in `require': cannot load such file -- sequel (LoadError) from /usr/local/lib/ruby/site_ruby/2.1.0/rubygems/core_ext/kernel_require.rb:54:in `require' from dna_in.rb:2:in `<main>'
使用 bundle install 安裝的 gem, 在代碼中 require, 運行時若是提示 cannot load such file, 使用 bundle exec 執行便可ruby