MongoDB Create User

use reporting
db.createUser(
  {
    user: "reportsUser",
    pwd: "12345678",
    roles: [
       { role: "read", db: "reporting" },
       { role: "read", db: "products" },
       { role: "read", db: "sales" },
       { role: "readWrite", db: "accounts" }
    ]
  }
)

Authenticate User Creation for Single Database
use products
db.createUser(
   {
     user: "accountUser",
     pwd: "password",
     roles: [ "readWrite", "dbAdmin" ]
   }
)