After updating to the new versions of the selenium-webdriver gem 2.48.0, the ruby console throws an error:
/Users/$USER/.rvm/gems/ruby-2.2.2/gems/appium_lib-7.0.0/lib/appium_lib/common/patch.rb:70:in `raw_execute': uninitialized constant Selenium::WebDriver::Remote::COMMANDS (NameError)
Reverting to 2.47.1 has resolved the issue for now.