Back End Small Feature

U have mobile apps native with that back end developed in fire-base so it database is fire base front end angurajs its where is even hosted then what the mobile apps do is that it list restaurants then when you go on them you find image of a restaurant description etc so what i want to add is a deal claim where in the app i will create a button on the restaurant page so that if in the back end i added deals user can click on the button and claim the button. I have low budged Thank you