module JSONAPI::Resources::AttributesDsl

def attributes(*attrs)
  @attributes ||= []
  @attributes.concat(attrs.map(&:to_sym))
  @attributes.uniq!
end

def creatable_fields(*fields)
  @creatable_fields ||= []
  @creatable_fields.concat(fields.map(&:to_sym))
  @creatable_fields.uniq!
end

def updatable_fields(*fields)
  @updatable_fields ||= []
  @updatable_fields.concat(fields.map(&:to_sym))
  @updatable_fields.uniq!
end