document that npm is required (for api gw package)

[erezh16]

Environment details:

• vagrant

Steps to reproduce the issue:

1. Clone the OW repo
2. Do a Vagrant build using ./hello
3. Build fails at routemgmt.yml because npm command is missing

Additional information you deem important:

• Travis build seems to be passing - but I haven't found why

[erezh16]

What version of npm should be installed?

[dubee]

@erezh16, the latest version of npm should work.

[nitikagarw]

Hi @dubee,
Does this task require updating the README here?
Thanks,
Nitika Agarwal

[rabbah]

I think that's a good place for it but only covers the standalone openwhisk.
There are several references in the README.md here https://github.com/apache/openwhisk/tree/master/ansible that should also get a similar note.

[nitikagarw]

Thanks, I'll give standalone openwhisk setup a try and document what works for me.