Add Postgres JSON support (manual cast only).

RedBeanPHP/QueryWriter/PostgreSQL.php

@@ -38,6 +38,7 @@ class PostgreSQL extends AQueryWriter implements QueryWriter
 	const C_DATATYPE_SPECIAL_MONEY    = 93;
 	const C_DATATYPE_SPECIAL_POLYGON  = 94;
 	const C_DATATYPE_SPECIAL_MONEY2   = 95; //Numbers only money, i.e. fixed point numeric
+	const C_DATATYPE_SPECIAL_JSON     = 96; //JSON support (only manual)
 	const C_DATATYPE_SPECIFIED        = 99;
 
 	/**
@@ -139,6 +140,7 @@ public function __construct( Adapter $adapter )
 			self::C_DATATYPE_SPECIAL_MONEY    => ' money ',
 			self::C_DATATYPE_SPECIAL_MONEY2   => ' numeric(10,2) ',
 			self::C_DATATYPE_SPECIAL_POLYGON  => ' polygon ',
+			self::C_DATATYPE_SPECIAL_JSON     => ' json ',
 		);
 
 		$this->sqltype_typeno = array();