Add error 500 - Internal Server Error to defines.php
Remove the auto increment from codes.sql
Edit the populate script (changed the tokens sizes)
Add multi query support to database library ($db->multi_query()) but there is no handling of returns
Edit oauth library to support token generation from client credentials, authorization code and refresh tokens.php
Endpoint /oauth/token supposedly finished (needs more testing)
Add library tokens to generate tokens and check their formating