require 'rubygems'
require 'bundler/setup'

# require your gems as usual
require "selenium-webdriver"

Selenium::WebDriver::Firefox.path = "/home/marc/Documents/firefox/firefox"
profile = Selenium::WebDriver::Firefox::Profile.new
proxy = Selenium::WebDriver::Proxy.new(:http => nil)
profile.proxy = proxy
driver = Selenium::WebDriver.for :firefox,:profile => profile
driver.navigate.to "http://google.com"

element = driver.find_element(:name,'q')
element.send_keys "Hello WebDriver!"
element.submit

puts driver.title

driver.quit

我收到以下错误：

/home/marc/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/selenium-webdriver-3.0.0.beta3.1/lib/selenium/webdriver/common/service.rb:115:in `connect_until_stable': unable to connect to Mozilla geckodriver 127.0.0.1:4445 (Selenium::WebDriver::Error::WebDriverError)

有人能帮我吗…？我几个小时都在努力,找不到问题……真的不知道该怎么办.

环境：

Ubuntu 16.04 LTS,
Firefox 45.0,
rbenv 2.3.1

其他问题：有人知道Selenium Ruby on Rails的一些例子吗？我找不到真正的好东西…文档很差:(