Since many text editors create files named with a ~ suffix as temp files, I created a rudimentary .gitignore file to ignore these files, as is common practice.
Ignore *~ files such as generated by Emacs and other editors.
You can set your own ignores, globally or locally, in your own Git config files. There's no reason this particular repo needs this to be set for everyone.
@dstillman I'm well aware of local Git exclusion. But it's common practice on every other project I've worked on to have a global .gitignore file with certain files that everyone would want to ignore. I believe this should be in the repo so that everyone doesn't have to set it. Anyway, this pull request is now superseded by #26 (which I made before seeing your comment here).
Excluding files actually generated by the project (as in #26) is fine. But there's no need for the project's .gitignore to deal with people's own editor-generated files, which they can exclude for all their repos if they use such an editor.