Add gitignore to prevent tracking unimportant files

[scottnm]

After compiling the hello world example in week0, I noticed git produced the following output

these object and executable files probably shouldn't ever be committed to the source tree. Recommend adding a simple .gitignore file at the root of the project which can tell git to ignore certain files

# ignores all object files and executables that may be generated when compiling
*.o
*.x

[rvdg]

Thank you. I am a relative ignoramus when it comes to github. Tend to make a mess of it... Can you check if I did it right?

[scottnm]

Yup it's correct! thanks