feat: Add db connection example config

.env.example

@@ -9,6 +9,13 @@ LOG_CHANNEL=daily
 DB_CONNECTION=sqlite
 DB_DATABASE=app.sqlite
 
+#DB_CONNECTION=<mysql | pgsql>
+#DB_HOST=<hostname | ip>
+#DB_PORT=<port number>
+#DB_DATABASE=<database>
+#DB_USERNAME=<user>
+#DB_PASSWORD=<password>
+
 BROADCAST_DRIVER=log
 CACHE_DRIVER=file
 QUEUE_CONNECTION=sync