Shopify + TapCart (Script Editor) and Ruby Developer Needed

I need a developer that knows their way around Shopify and TapCart. We have a Shopify store that uses TapCart to make the website into a mobile app. Now we want to add a discount through Shopify Script editor that only ones and applies on the mobile app but the script is getting errors and i need someone to guide me on how i can do this. Knowing Ruby is a place, as the snippet is Ruby and so is Script Editor.