GIT - pushing to (GitHub) origin master does nothing

When it says Up to date it means your local repository and your remote repository are one and the same, that is you have not made any changes to your local repo that needs to be pushed to the remote repo.

If you have indeed changed the files then you must have forgot to commit it.

If you had created new files then you must add it. To add files use

git add .

then to commit all the edited files use

git commit -am "Commit message"

then do

git push origin master

It might be the case that you are on another branch than the master branch, then type:

git push origin HEAD:master

so git understands that you want to push up current HEAD and not the master branch.