ruby `require': cannot load such file

使用 RubyMine 新建 gem 工程后，运行 helloworld 程序报错，错误信息如下：

"D:\Program Files\Ruby24-x64\bin\ruby.exe" -e $stdout.sync=true;$stderr.sync=true;load($0=ARGV.shift) D:/rubymine_projects/helloworld/lib/helloworld.rb
D:/Program Files/Ruby24-x64/lib/ruby/2.4.0/rubygems/core_ext/kernel_require.rb:55:in `require': cannot load such file -- helloworld/version (LoadError)
	from D:/Program Files/Ruby24-x64/lib/ruby/2.4.0/rubygems/core_ext/kernel_require.rb:55:in `require'
	from D:/rubymine_projects/helloworld/lib/helloworld.rb:1:in `<top (required)>'
	from -e:1:in `load'
	from -e:1:in `<main>'

Process finished with exit code 1

原因是 helloworld.rb 文件中使用了 require 关键字引用了相对路径：

require "helloworld/version"

module Helloworld
  # Your code goes here...
  puts "hello";
end

将 require 修改为 require_relative 后，问题解决。