Create a .csv to create users at once in [https://admin.google.com] and sends emails to people with the credentials for first login (first login forces to change password).
The input is a file named guys.csv with 3 columns: LastName,FirstName,ExistingEmail.
Then run the program, it will write a guys.priv.csv with random passwords. You need to import this in [https://admin.google.com/u/0/users].
Once uploaded, press enter in the console and it will send the emails!