criar usuário normal

use dbnome

var user = { "user" : "website", "pwd" : "abc123", roles : [ { "role" : "readWrite", "db" : "dbnome" } ] }

db.createUser(user);

exit

criar usuário admin

db.createUser( { user: "user", pwd: "password", roles:[{role:'root', db:'admin'}] })

URI funcionando

mongodb://user:password@host:port/db?authSource=admin