bundler under npm install fails to execute (wrong ruby version)

if I run `npm install` the script dies with
```
Your Ruby version is 2.0.0, but your Gemfile specified 2.4.0
```

however if I run `bundle install --binstubs ./examples/ios && bundle exec pod install --project-directory=./example/ios/` all goes fine

my env:
```
$ ruby -v
ruby 2.4.0p0 (2016-12-24 revision 57164) [x86_64-darwin16]

$ bundler -v
Bundler version 1.14.6
```

Any idea? (sorry, not versed with ruby :( )

Start by examining the npm install script and the Gemfile, then compare the Ruby selected by that script with the reported Ruby 2.4.0 environment. Done means npm install uses the Gemfile's required Ruby version and completes successfully, matching the manual bundle install and pod install commands.

Written by the indexing model from the issue text.