How to use the software:
0. This python code is written for python3.
1. You can start the program by double clicking on the main.py file.
2. You choose an option by typing in the option number. For example, you wan to choose "1. Load", you need to type in "1" and press enter.
3. You need to load some data from files by choosing the "Load" option, otherwise you won't see anything interesting or even login.
4. You can use some non-administrative options before you login. But unlike non-administrative users, you cannot reserve a room or an activity.
5. You can login by choosing "Login" option. Here are the existing users:
    ID: 0. Password: 0. Administrative user.
    ID: 1. Password: 1. Non-administrative user.