> execute.rb
> lib

> my_class.rb

在execute.rb中,我有以下代码：

#!/usr/bin/ruby

require 'lib/my_class'

my_object= MyClass.new

my_object.some_method

这是my_class.rb的代码：

class MyClass
    def some_method
        puts 'OK'
    end
end

所以,我尝试运行execute.rb：

ruby execute.rb

但我收到这个错误：

/home/vagrant/.rvm/rubies/ruby-2.0.0-p195/lib/ruby/site_ruby/2.0.0/rubygems/core_ext/kernel_require.rb:45:in `require': cannot load such file -- lib/my_class (LoadError)
    from /home/vagrant/.rvm/rubies/ruby-2.0.0-p195/lib/ruby/site_ruby/2.0.0/rubygems/core_ext/kernel_require.rb:45:in `require'
    from execute.rb:3:in `<main>'

谁能帮我？我会感激任何帮助.
非常感谢.