添加sql脚本执行的字符编码

此处不指定字符编码在docker镜像启动时候执行这个sql时候会报错
/usr/local/bin/docker-entrypoint.sh: running /docker-entrypoint-initdb.d/tables_xxl_job.sql
mysql: [Warning] Using a password on the command line interface can be insecure.
ERROR 1406 (22001) at line 104: Data too long for column 'title' at row 1

doc/db/tables_xxl_job.sql

@@ -5,6 +5,7 @@
 CREATE database if NOT EXISTS `xxl_job` default character set utf8 collate utf8_general_ci;
 use `xxl_job`;
 
+SET NAMES UTF8;
 
 CREATE TABLE `xxl_job_info` (
   `id` int(11) NOT NULL AUTO_INCREMENT,