Netlify deploy needs themes/etch to be added as a submodule

[meerasndr]

This Netlify deployment error was fixed by adding this to the .gitmodules file:

[submodule "themes/etch"]
	path = themes/etch
	url = https://github.com/LukasJoswiak/etch.git

It would be useful to include this in the setup instructions. Maybe instead of the above manual way, this can be suggested(instead of cloning)-
git submodule add https://github.com/LukasJoswiak/etch.git themes/etch