Invalid Theme Folder and Missing Jasper-api

Hi,

I downloaded and installed Jasper by adding the line:
`gem: "jasper"` to my Gem file. I then ran `bundle install` from the terminal. Finally, I switched the theme flag in my _config-yml file from `theme: minima` to `theme: jasper`.
I then tried to run `bundle exec jekyll serve` and got this error messages:

Invalid theme folder: _sass
Invalid theme folder: _includes
Dependency Error: Yikes! It looks like you don't have jasper-api or one of its dependencies installed. In order to use Jekyll as currently configured, you'll need to install this gem. The full error message from Ruby is: 'cannot load such file -- jasper-api' If you run into trouble, you can find helpful resources at https://jekyllrb.com/help/!

I checked if jasper-api is installed (with `gem list`) and it seems like it is:

...
io-console (default: 0.4.5)
jasper (0.0.8)
jasper-api (0.0.8)
jasper-backend (0.0.8)
jasper-cli (0.0.8)
jasper-core (0.0.8)
jasper-frontend (0.0.8)
jasper-sample (0.0.8)
jekyll (3.8.5)
jekyll-feed (0.11.0)
jekyll-sass-converter (1.5.2)
jekyll-seo-tag (2.5.0)
jekyll-watch (2.1.2)
...

I am rather new at this and I can't seem to figure out what is going on here. Any help would be appreciated!

PS: I am working on MacOS High Sierra (v 10.13.6) and have jekyll (v 3.8.5)