Resolve "CONTRIBUTING.md file"

Closes #9

See merge request !4

added CONDUCT.md file

Closes #8

See merge request !3

added the boilerplate contributor-covenant conduct to CONDUCT.md

added more gitignore files

Closes #7

See merge request !1

- using __file__, the path is now correct for any working directory

- load_dataset now imports the default dataset if no parameter is given

- the default dataset is imported from "./data/GamingStudy_data.csv"

- load_data now uses the given parameter "filename"

- the hardcoded path used to import the dataset was removed