create user and database in mongo 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: mongodb create admin user for all databases

use admin
db.createUser({ user: "mongoadmin" , pwd: "mongoadmin", roles: ["userAdminAnyDatabase", "dbAdminAnyDatabase", "readWriteAnyDatabase"]})