Watir is a web testing framework implemented in ruby, but can be used for testing or automating any web service.

gem install watir-webdriver
#or in your Gemfile
gem "watir-webdriver"

For Internet Explorer on Windows

require 'watir'
browser = Watir::Browser.new :ie

Firefox or Chrome

require 'watir-webdriver'
browser = Watir::Browser.new :firefox
# OR
browser = Watir::Browser.new :chrome

For OS X and Automating chrome I had to install the chrome driver from chromedriver or using homebrew.

brew install chromedriver

A simple script might be:

require 'watir-webdriver'
browser = Watir::Browser.new :chrome
browser = Watir::Browser.start 'www.google.com'
puts browser.title
browser.close

This launches a graphical browser and performs the actions requested.

Headless

There is a way to make these compatible with severs which do not have a graphics system, by installing the headless gem.

gem install watir-webdriver
gem install headless
#or in your Gemfile
gem "watir-webdriver"
gem "healdess"

The headless gem uses xvfb to perform graphical actions. If you are not on headless machine these will still be visible.

require 'watir-webdriver'
require 'headless'

headless = Headless.new
headless.start

browser = Watir::Browser.start 'www.google.com'
puts browser.title
browser.close

headless.destroy