Getting rid of the ruby dependency

[jwoertink]

I'd like to do this in all crystal, but there's a bit of a lack of support for things I need.

1. Guard like package for auto-reload to replace guard-kemal
2. Sass & less compilers
3. es6 & coffeescript compilers

These are some that I found, but I'll need to play with them more to see how stable they are.
1 - https://github.com/f/guardian
2 - https://github.com/vonKingsley/crass
3 - https://github.com/jessedoyle/coffee-script