Global gitignore

Following this guide https://help.github.com/articles/ignoring-files/#create-a-global-gitignore, I have a global gitignore at `~/.gitignore`

```
:; git config --get core.excludesfile
~/.gitignore
```

The app is not respecting this setting however and does not ignore files set in there (such as `.swp` file). Would be great for the app to take into account this setting.
