Users can favorite a seller

[askingalot]

Given a user wants to view all products being sold by another user
When the user clicks on an affordance next to a seller's name
Then the seller will be added to the current user's favorites list

Given a user wants to view all products from their favorite sellers
When the user clicks on the Favorites affordance in the navigation area
Then all product being sold by each of the current user's favorited seller must be listed, grouped by seller