The goal of the spike is to define the necessary steps to introduce Request Preferences per User in mod-circulation.

Spike results:

1. Storing request preferences in mod-circulation-storage:

We will add table user_request_preferences to mod-circulation-storage. user_request_preferences will store user preference fields in json format. 

...

5) PUT /request-preference-storage/request-preference/{id} - update request preference

3. Attributes of user request preference:

id - Unique request preference ID
userId - UUID of user associated with this request preference
holdShelf - Whether 'Hold shelf' option is available to the user.
delivery - Whether 'Delivery' option is available to the user.
defaultServicePointId - UUID of default service point for 'Hold shelf' option
defaultDeliveryAddressTypeId - UUID of user's address type

Example of request preference:

{
  "userId": "1e425b93-501e-44b0-a4c7-b3e66a25c42e",
  "holdShelf" : true,
  "delivery": true,
  "defaultServicePointId": "22beccec-8d77-4a97-906a-37cc26b070e5",
  "defaultDeliveryAddressTypeId": "27a1b086-20ac-4b1d-b6ac-3be353383f3d",
  "fulfillment": "Delivery"
}

...

4. POC: 

Created a draft pull request with simple implementation of request-preference-storage endpoints
https://github.com/folio-org/mod-circulation-storage/pull/200