Implemented get all users, create user and delete a user

Note that deleting a user works as checked in the webconsole on https://[domain].hipchat.com/people but in the test i get the wrong status code with the error: 
{
error: {
    code: 400
    message: "Can only remove participants to private rooms"
    type: "Bad Request"
}
}
I don't know if this is an API error or that maybe i'm missing something.