PHP Adapter pattern - can you explain?

Im trying to practise adapter design pattern in php and I found this task http://tech.dixons.cz/test

so I decided to try it out. Here is my job,

https://github.com/janvacek/AdapterTest

it is not exactly same as it propably should be, but I tried my best, can you explain me what is wrong and what I should change + maybe tell me how the "detail" method should look like? Because the main meaning of this task is that when I decide to add more database drivers, I should not change this method, so I dont know how to do that correctly.

Thank you guys!