foreignKey(_:references:inSpace:_:onDelete:onUpdate:name:)

@discardableResult func foreignKey(_ field: FieldKey, references foreignSchema: String, inSpace foreignSpace: String? = nil, _ foreignField: FieldKey, onDelete: DatabaseSchema.ForeignKeyAction = .noAction, onUpdate: DatabaseSchema.ForeignKeyAction = .noAction, name: String? = nil) -> Self