Update .gitmodules
Update .gitmodules

Hello there,

I would like to add Tachyons theme to the Hugo main repository.

Thanks,

Marlon
Conflicts:
	.gitmodules

spf13/hugoThemes,dim0627/hugoThemes,rakuishi/hugoThemes,Nytoca/hugoThemes,ebr/hugoThemes,vashstorm/hugoThemes,emaniacs/hugoThemes,lichenbuliren/hugoThemes