Add docstrings to all functions and clean up code

[Paulinakhew]

• this issue just has to do with code readability
• in the future, when building this out, each function should be properly labeled and its purpose should be easy to identify
• this website has a lot of popular docstrings formats
• [ ] Add docstrings to all functions in model.py
• [ ] Add docstrings to all functions in controller.py
• [ ] Add line separations within functions
• [ ] remove unnecessary commented out code
• [ ] implement flake8