Once you have a set of tests, it's good to run them on a regular basis or when a new code is added to the code base. This is where the Continuous Integrations(CI) comes into play. There are different platforms that can be used for CI - some require local installation, others are public and free for open-source projects. To mention some of them:
A descriptive real example of CI you can find in Plugin UI Tests article that demonstrates step by step all the needed actions.
In short, you need a .travis.xml on the root of the repository which tells travis what machine instances to setup and which commands to execute. Then in the UI testing stage defined in your travis file, run the nativescript-dev-appium command you usually use by providing proper --runType and just add --sauceLab flag that tells plugin to execute tests in SauceLabs instead locally.