public void deleteUser(User user) {
        System.out.println(users);
        System.out.println(user);
        System.out.println("Started delete user");
        if(users.contains(user)) {
            int i = 0;
            System.out.println("delete user: " + user);
            while(i<categories.size()) {
                Category c = categories.get(i);
                System.out.println("Checking Category: " + c);
                int j = 0;
                if(c.getUser().equals(user)) {
                    removeCategory(c);
                    System.out.println("called RemoveCategory");
                }  else {
                    while(j<c.getMessages().size()) {
                        int k = 0;
                        Message m = c.getMessages().get(j);
                        System.out.println("Checking messages: " + m);
                        System.out.println("");
                        if(m.getUser().equals(user)) {
                            c.removeMessage(m);
                            System.out.println("called RemoveCategory");
                        } else {
                            while(k<m.getComments().size()) {
                                Comment cc = m.getComments().get(k);
                                System.out.println("Checking comment: " + cc);
                                if(cc.getUser().equals(user)) {
                                    m.removeComment(cc);
                                    System.out.println("Removing comment");
                                }
                                k++;
                            }
                            j++;
                        }
                    }
                }
                i++;
            }
        }
    }