Readme Needs Update

[glomyst]

Instructions are too vague.

[junhoyeo]

Instructions are too vague.

@glomyst I would be happy to enhance the quality of it for sure! Do you have any specific "instructions" that you need?

[glomyst]

So there are two instructions given.

1. Install -> npm install --save-dev vercel-submodules
2. Override the build command -> vercel-submodules --all && [my build command]

Vercel gives the error: vercel-submodules: command not found

[ctian1]

I also ran into this, it should be npx vercel-submodules instead of just vercel-submodules

[junhoyeo]

I also ran into this, it should be npx vercel-submodules instead of just vercel-submodules

Thanks @glomyst @ctian1, updated in 04156fe