README.md has nonfunctional API example code

[padalev]

I executed the API example code provided under the section "API". This returned with an error for the import of the Category class.

After some digging I came to the conclusion that the example uses deprecated code. Additionally it includes some misspelling (Acessory instead of Accessory).

I'm under the impression that the example is supposed to be identical to the contents of main.py This pull request exchanges the code example with the contents of main.py