PHP and MySQL: Coding a plugin for a social network

You are to adjust the chat system in the social network script (find the demo of the social network here : [login to view URL]) Also you are to code the "Login via Vkontakte" function. Facebook log in already works - so you can use it as an example while coding Vkontakte log in. Please find the thorough description of the task in the file attached. P.S. The code of the social network script is well commented and is written in accordance with the standards. The files and variables names are also adequate - so you can easily understand what functions they perform. There will be one more task (the same difficulty and price) if the task is fulfilled properly. If you have any questions, please ask.