how to use mongo db for creating user and login code example

Example 1: mongodb add user

use <your database>
db.createUser({
  user: '<some username>',
  pwd: passwordPrompt(),
  roles: [{
    role: 'readWrite',
    db: '<your database>'
  }]
})

Example 2: mongo db shell user login

$ mongo admin -u uname -p 'password'