add_prerelease_option

# File lib/rubygems/version_option.rb, line 42
  def add_prerelease_option(*wrap)
    add_option("--[no-]prerelease",
               "Allow prerelease versions of a gem", *wrap) do |value, options|
      options[:prerelease] = value
      options[:explicit_prerelease] = true
    end
  end