Group.java

import java.util.ArrayList;

/*
    Represents a Group of Users.
 */
public class Group {

    private String groupID;
    private ArrayList<User> users;

    public void addUser(User user) {
        users.add(user);
    }

    public void removeUser(User u) {
        users.remove(u);
    }

    //Getters

    public String getID() {
        return groupID;
    }

    public ArrayList<User> getUsers() {
        return users;
    }
}