fixing MYSQL_USER not show other databases.

mysql/docker-entrypoint-initdb.d/createdb.sql.example

@@ -1,8 +1,28 @@
 ###
 ### Copy createdb.sql.example to createdb.sql
-### then uncomment and set database name to create you need databases
+### then uncomment then set database name and username to create you need databases
+#
+# example: .env MYSQL_USER=appuser and need db name is myshop_db
+#
+#    CREATE DATABASE IF NOT EXISTS `myshop_db` ;
+#    GRANT ALL ON `myshop_db`.* TO 'appuser'@'%' ;
+#
+###
+### this sql script is auto run when mysql container start and $DATA_SAVE_PATH/mysql not exists.
+###
+### if your $DATA_SAVE_PATH/mysql is exists and you do not want to delete it, you can run by manual execution:
+###
+###     docker-compose exec mysql bash
+###     mysql -u root -p < /docker-entrypoint-initdb.d/createdb.sql
 ###
 
-#CREATE DATABASE IF NOT EXISTS `dev_db_1` ;
-#CREATE DATABASE IF NOT EXISTS `dev_db_2` ;
-#CREATE DATABASE IF NOT EXISTS `dev_db_3` ;
+#CREATE DATABASE IF NOT EXISTS `dev_db_1` COLLATE 'utf8_general_ci' ;
+#GRANT ALL ON `dev_db_1`.* TO 'default'@'%' ;
+
+#CREATE DATABASE IF NOT EXISTS `dev_db_2` COLLATE 'utf8_general_ci' ;
+#GRANT ALL ON `dev_db_2`.* TO 'default'@'%' ;
+
+#CREATE DATABASE IF NOT EXISTS `dev_db_3` COLLATE 'utf8_general_ci' ;
+#GRANT ALL ON `dev_db_3`.* TO 'default'@'%' ;
+
+FLUSH PRIVILEGES ;