Merge pull request #71 from heroku/diet

Ship the Diet Buildpack!
add empty bin/release file so as not to break things that expect it to be there
Merge pull request #72 from heroku/add-empty-release-file

add empty bin/release
Set default NODE_ENV to 'production'
add comment about npm executable
be more clear about the effect of `npm prune`
Make the caching messages more clear.
CONTRIBUTING.md doesn't exist anymore. Refer instead to README.md
fix a broken assertion
bin/release should emit a valid yaml mapping.
make bin/release comply with published Buildpack API
Merge pull request #78 from yougov/master

Make bin/release comply with published Buildpack API
Add support for custom .npmrc
Add a test for custom .npmrc support
Merge pull request #79 from gemfury/master

Add support for custom .npmrc
only prune when node_modules directory is restored from cache. Fixes #75
Merge pull request #80 from heroku/only-prune-on-cache-restore

only prune when node_modules directory is restored from cache. Fixes #75
always use https
Merge branch 'master' of github.com:heroku/heroku-buildpack-nodejs
Add scripts.start to Procfile from package.json

If no Procfile exists and there is a scripts.start in package.json, add
the scripts.start script as the 'web' process type to a new Procfile.