Game hosting via MIT App Inventor

I searched the AI2 Gallery for "poker", and found no multi-player examples.

So you are on your own for that.

However, here is a good start on a data model for your game ...

Vertabelo is a nice online data modelling tool. I have a free online account, at its limit.

Time spent learning data modelling is time well spent, if you intend to write serious software.