Feature/directory disable

Copying and pasting the entire thing isn't a great idea. 
Rather do something like this :+1: 

```
var choices =  [
                 new Choice("articles", _.gettext("Articles")),
                 new Choice("opinions", _.gettext("Opinions")),
                 new Choice("wwsd", _.gettext("What would Shangazi do?")),
                 new Choice("quiz_start", _.gettext("Weekly quiz")),
             ]
if (self.check_directory(im)) {
    choices.push(new Choice("directory", _.gettext("Directory")))
}
```
Then use ``choices`` where the array currently is