mongo添加新的数据库并为新数据库添加可读可写的用户

> show databases;
admin   0.000GB
config  0.000GB
local   0.000GB
plante  0.000GB
test01  0.000GB
test02  0.001GB
> use longyan
switched to db longyan
> db.longyan.insert({"name":"test"})
WriteResult({ "nInserted" : 1 })
> show databases
admin    0.000GB
config   0.000GB
local    0.000GB
longyan  0.000GB
plante   0.000GB
test01   0.000GB
test02   0.001GB
> use longyan
switched to db longyan
> 
db.createUser(
   {
     user: "用户名",
     pwd: "密码",
     roles: [ "readWrite" ]
   }
);