Writing many unnecessary lines to .gitignore

[m11m]

I found that .gitignore had many lines written to it, I'm not sure how big of an issue this is, but at least was annoying me enough to inspire a bit of code.

I'm not sure how useful it is, only recently started writing Elixir code and only started looking at this codebase yesterday, but here it is FWIW: m11m@df4ee5f

Thanks!