~ $ ruby main.rb
Traceback (most recent call last):
        2: from main.rb:1:in `<main>'
        1: from /app/vendor/ruby-2.5.0/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require'
/app/vendor/ruby-2.5.0/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require': cannot load such file -- bzip2 (LoadError)