Added an appium test

Appium (http://appium.io/) is an automation framework for mobile apps. I created a test for Cheddar using Ruby and Appium. In order to run it, launch Appium from the client, locate the cheddar_test.rb file in your terminal, and type "rspec cheddar_test.rb". 

The test will make and archive lists, allowing you to quickly and easily test the functionality of the app.