added possibility to save messages to be translated

framework/i18n/DbMessageSource.php

@@ -22,7 +22,7 @@ use yii\db\Query;
  *
  * ~~~
  * CREATE TABLE tbl_source_message (
- *     id INTEGER PRIMARY KEY,
+ *     id INTEGER PRIMARY KEY AUTO_INCREMENT,
  *     category VARCHAR(32),
  *     message TEXT
  * );

framework/messages/config.php

@@ -42,6 +42,6 @@ return [
 		'.hgkeep',
 		'/messages',
 	],
-	// Generated file format. Can be either "php" or "po".
+	// Generated file format. Can be either "db", "php" or "po".
 	'format' => 'php',
 ];