Included in Spacemacs develop branch

[syl20bnr]

Hi brantou,

Great layer for Crystal, I included it in develop branch.
https://github.com/syl20bnr/spacemacs/tree/develop/layers/%2Blang/crystal

I tested it with simple crystal files and it seems to work OK.
Let me know if there is any mistakes, and PRs are always welcome of course :-)

Cheers,
syl20bnr

[brantou]

@syl20bnr Great!