Cannot find module 'underscore'

[sebastiancarlsson]

I'm new to Keystone and just tried this generator for the first time. When I run node keystone I get

module.js:327
    throw err;

Error: Cannot find module 'underscore'

Steps to reproduce:

1. Run yo keystone with the following configuration
   
2. Run node keystone

Searching through the generated files I can find references to underscore in templates/views/helpers/index.js.

Workaround:
npm install --save underscore will fix this problem