Here's how to run your Appium Inspector saved ruby boilerplate tests.
1) Start the Appium server in terminal with this, and leave this terminal window open.
$ appium &
2) While the appium server is running in the previous terminal window, open a new terminal window and navigate to the directory where your tests are located and run them with this.
$ ruby "your_test.rb"
That should execute your Appium test you recorded with the Appium inspector.
If you have the Appium GUI running/open, you may have node issues about the same port already in use. If this happens simply run this in terminal.
$ killall node
If you don't already have the appium server installed you can install it by running this in terminal which requires npm to be installed.
$ npm install -g appium
Hope this helps.