add jsonb in postgresql

docs/fields/field-types.md

@@ -140,6 +140,13 @@ You can pass `timezone=True` for timezone aware database column.
 * Sqlalchemy column: `sqlalchemy.JSON`  
 * Type (used for pydantic): `pydantic.Json` 
 
+### JSONB
+
+`JSONB()` has no required parameters, only support it in the postgresql.
+
+* Sqlalchemy column: `sqlalchemy.dialects.postgresql.JSONB`  
+* Type (used for pydantic): `pydantic.Json` 
+
 ### LargeBinary
 
 `LargeBinary(max_length)` has a required `max_length` parameter.  

ormar/fields/model_fields.py

@@ -520,6 +520,29 @@ class JSON(ModelFieldFactory, pydantic.Json):
         return sqlalchemy.JSON()
 
 
+class JSONB(JSON):
+    """
+    JSONB field factory that construct Field classes and populated their values,
+    only support postgresql
+    """
+
+    _type = pydantic.Json
+    _sample = '{"jsonb": "jsonb"}'
+
+    @classmethod
+    def get_column_type(cls, **kwargs: Any) -> Any:
+        """
+        Return proper type of db column for given field type.
+        Accepts required and optional parameters that each column type accepts.
+
+        :param kwargs: key, value pairs of sqlalchemy options
+        :type kwargs: Any
+        :return: initialized column with proper options
+        :rtype: sqlalchemy Column
+        """
+        return sqlalchemy.dialects.postgresql.JSONB()
+
+
 if TYPE_CHECKING:  # pragma: nocover # noqa: C901
 
     @overload