GraphQL: User's Store Items Query

[Alaina-Noel]

As a user of the API, I want to be able to retrieve a list of a user's store items based on the user id passed in.
{
userStoreItems(user: id) {
stores {
id
name
address
storeItems {
id
price - will be constant
itemName
photoUrl
quantity - user store item attribute
itemTotal - quantity * price
}
storeTotalPrice # all items at one particular store
}
grandTotalPrice # all items at all stores and all items
}
}

The endpoint should return the list of stores in JSON format, with each store containing the following fields:

• id: A unique identifier for the store
• name: The name of the store
• address: The address of the store
  A nested list of store items that include:
• storeItemId - unique identifier for the store item
• price: The price of the store item
• itemName: The name of the item
• photoUrl - the url for the photo associated with that store's item
• quantity - the quantity of that item
• itemTotal - quantity * price
  Also included will be
• storeTotalPrice - the total cost of all items at a particular store - this is included at the same level as stores attributes
• grandTotalPrice - all items at all store's prices totaled - this is included at the same level as stores

Documentation: Update the README file so that the changes are reflected:

• Query readme updated
• Expected Response updated