Directive possibleTypes

[Václav Pelíšek]

Directive possibleTypes to specify type associated with ID parameter.

Inspired by github API:

"""
Defines what type of global IDs are accepted for a mutation argument of type ID.
"""
directive @possibleTypes(
  """
  Abstract type of accepted global ID
  """
  abstractType: String

  """
  Accepted types of global IDs.
  """
  concreteTypes: [String!]!
) on INPUT_FIELD_DEFINITION

[Václav Pelíšek]

Pre-Resolver could be added so graphpinator automatically selects item from database and passes it to resolve function instead of string ID.