npm install fail

[macmenco]

The jenkins build fails with

npm ERR! path /var/jenkins_home/workspace/solitaire/node_modules/http-server/bin/http-server
npm ERR! code ENOENT
npm ERR! errno -2
npm ERR! syscall chmod
npm ERR! enoent ENOENT: no such file or directory, chmod '/var/jenkins_home/workspace/solitaire/node_modules/http-server/bin/http-server'
npm ERR! enoent This is related to npm not being able to find a file.
npm ERR! enoent

As suggested in https://stackoverflow.com/questions/17990647/npm-install-errors-with-error-enoent-chmod, creating a .npmignore fixes the issue.