should be able to pass a nice path into the generator

:green_heart: 
I'd prefer we do something like
```ruby
clean_path = Pathname.new(file_path).cleanpath.to_s
```
and not refer to `file_path` again; cleaning first and then also referring to the 'unclean' argument confuses the flow, in my opinion (and it doesn't seem to affect the `Pathname` constructor).