use mydbdb.createUser( { "user" : "sa",                 "pwd": "sa",                 "customData" : { employeeId: 12345 },                 "roles" : [ { role: "clusterAdmin", db: "admin" },                             { role: "readAnyDatabase", db: "admin" },                             "readWrite"                             ] },               { w: "majority" , wtimeout: 5000 } )mongo -u sa -p sa --authenticationDatabase mydb