[symfony#2920] Re-adding fields that were available in Doctrine for Symfony 2.3

Author: weaverryan

book/doctrine.rst

@@ -1449,6 +1449,11 @@ using. The following types are supported in Doctrine:
   * ``object`` (serialized and stored in a ``CLOB`` field)
   * ``array`` (serialized and stored in a ``CLOB`` field)
   * ``blob`` (mapped to a resource stream)
+  * ``simple_array`` (serialized using :phpfunction:`implode()` and :phpfunction:`explode()`,
+    with a comma as delimiter, and stored in a ``CLOB`` field)
+  * ``json_array`` (serialized using :phpfunction:`json_encode()` and :phpfunction:`json_decode()`,
+    and stored in a ``CLOB`` field)
+  * ``guid``
 
 For more information, see Doctrine's `Mapping Types documentation`_.