implementing postgres types like json and json

[NPCRUS]

I have red the documentation on custom type mappers and wasn't able to make it work:

object JsonbType extends StringType {
  override def castTypeString: String = "JSONB"
  override def jdbcType: JDBCType = JDBCType.OTHER
}

and I get: ERROR: column "???" is of type jsonb but expression is of type character varying Hint: You will need to rewrite or cast the expression

Does anybody have any ideas about this?