Username and password authentication script

[eluser]Phil Sturgeon[/eluser]
The main problem here is that you are not loading the database library in check_login_data(). You should load database in /config/autoload.php to save having to load it in each model method.

A few other small things...

get_users($username)
This name is confusing. Suggests it will return multiple but only returns 1.

get_last_ten_entries()
Function doesnt limit to 10 at all, will return all users.

check_login_data($username, $password)
Return the user id and check its over 0 in your controller or something similar, but there is no need to return the pass. Also, you are not actually checking the password, should probably uncomment that ^_^