update config.sample.php generated documentation

admin_manual/configuration/configuration_config_sample_php.rst

@@ -927,6 +927,25 @@ to be fetched in addition to any requested file.
 
 One way to test is applying for a trystack account at http://trystack.org/
 
+::
+
+	'supportedDatabases' => array(
+		'sqlite',
+		'mysql',
+		'pgsql',
+		'oci',
+		'mssql'
+	),
+
+Database types that are supported for installation.
+
+Available:
+	- sqlite (SQLite3)
+	- mysql (MySQL)
+	- pgsql (PostgreSQL)
+	- oci (Oracle)
+	- mssql (Microsoft SQL Server)
+
 ::
 
 	'custom_csp_policy' =>