求翻译：用户还可以添加，删除，修改联系人，添加，删除联系人分组等，其中用到了Tomcat做web服务器，mysql做数据库，用来对用户和联系人的相关信息进行操作。是什么意思？

Users can also add, delete, modify contacts, add, and delete a contact group, which used the tomcat web server, mysql to do the database used for the user and contact information.

Users can also add, delete, modify, add, delete, group contacts, which used to be the Tomcat Web server, MySQL database and is used to make user and contact information.

正在翻译，请等待...

Users can also add, delete, and modify contacts, add, delete a contact group, which uses the Tomcat Web server, MySQL database, used to operate on the user and contact information.

The user also may increase, deletes, the revision contact person, the increase, deleted the contact person grouping and so on, in which uses Tomcat to make the web server, mysql makes the database, used for carries on the operation to the user and contact person's related information.