update README

docker/mariadb/10.3.17/README.md

@@ -85,4 +85,13 @@ start slave;
 
 and you're done.
 
-check with `SHOW SLAVE STATUS \G`
+check with `SHOW SLAVE STATUS \G`
+
+# proxysql
+
+create `monitor` user for proxysql
+
+```sql
+CREATE USER 'monitor'@'%' IDENTIFIED BY 'monitor';
+GRANT SELECT on sys.* to 'monitor'@'%';
+```