Organising MVC App with virtual model using external API

Question

I am creating a rails app with following constraints

• It has no database
• It uses a web API to store and retrieve the data
• The connection to the web API is via a custom gem.
• The Gem has a basic functionality to make a web API call based on the parameters given.
• I have 2-3 different kinds of object that I can think of ( or may be more precisely virtual model )

How should the structure of my program be ?

• Should I incorporate all the method calls within the gem ?
• Should I create models and put the api related calls in there (then through the gem's basic method)
• Should I just ignore the model and put everything in the controller . ?

The second method seems most appropriate , but then all the methods from model would be static and I would be calling all methods in essence without any objects.