NPM installation for non-admin users should add path explicitly

[sswaroopgupta]

For a non-admin windows-user, the steps mentioned in the getting started page is not working as expected

The documentation should include -
For a non-admin user, after npm install -g @getgauge/cli the path where gauge is installed should be added explicitly.

[zabil]

Prefer displaying a message post install on npm to non admin users.
Or run a script to add it safely to the path with the user's permission as a post install command.
https://docs.npmjs.com/misc/scripts#examples