Сам разобрался.
require 'watir'
require 'proxy_chain_rb'
require 'selenium-webdriver'
USERAGENT = File.readlines("user_agents.txt").sample
options = Selenium::WebDriver::Chrome::Options.new
options.add_emulation(user_agent: (USERAGENT))
u_proxy = File.readlines("proxy.txt").sample
real_proxy = u_proxy
server = ProxyChainRb::Server.new
generated_proxy = server.start(real_proxy)
proxy = {
http: generated_proxy,
ssl: generated_proxy
}
caps = Selenium::WebDriver::Remote::Capabilities.chrome(:proxy => proxy)
driver = Selenium::WebDriver.for :chrome, :desired_capabilities => caps, options: options
driver.execute_script('return navigator.userAgent')
driver.get("https://raskruty.ru/tools/ip/")