[Bug] README.md Installation step should describe required Menu.Main config.toml setting

[rajeshduggal]

Expected behavior

Following hugo getting started and castanet installation instructions should result in a basic rendered hugo site.

Actual behavior

After following hugo getting started and castanet installation hugo server -D displays an error related to Site.Menus.

Reproduction Steps

Starting from scratch, follow hugo getting started steps and install the castanet theme. hugo server -D displays an error no rendered website.

Operating System and Version

n/a

Web Browser and Version

n/a

Hugo Version

hugo v.0.36.1 windows/amd64

[rajeshduggal]

This fix for this could be just to document adding the menu to the config.toml as a required step in the installation instructions.

[mattstratton]

I think I can actually add some code that will check to see if there are any menu elements before trying to display them.