Error when deploying nodejs app to Heroku

I've been using this express app boilerplate - https://github.com/developit/express-es6-rest-api. After following instructions how to deploy to Heroku via CLI I get no error in the build log. However opening the app url results in - "Application error".

I use c9 as en editor so I have Node v6, npm v 5.

Log output looks like this:

2017-06-05T10:44:46.900471+00:00 app[web.1]: npm ERR! Please include the following file with any support request:
2017-06-05T10:44:46.900611+00:00 app[web.1]: npm ERR!     /app/npm-debug.log
2017-06-05T10:44:46.989962+00:00 heroku[web.1]: Process exited with status 1
2017-06-05T10:44:47.002321+00:00 heroku[web.1]: State changed from starting to crashed
2017-06-05T10:46:42.536395+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/" host=xxx-backend.herokuapp.com request_id=178ed6ba-5aad-47d2-a08b-97d1af04275c fwd="81.205.254.193" dyno= connect= service= status=503 bytes= protocol=https
2017-06-05T10:46:43.240301+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/favicon.ico" host=xxx-backend.herokuapp.com request_id=e1578893-aa02-4544-832e-32a6a836e208 fwd="81.205.254.193" dyno= connect= service= status=503 bytes= protocol=https
Disconnected from log stream. There may be events happening that you do not see here! Attempting to reconnect...
2017-06-05T10:44:46.894354+00:00 app[web.1]: npm ERR!     npm bugs express-es6-rest-api
2017-06-05T10:44:46.894516+00:00 app[web.1]: npm ERR! Or if that isn't available, you can get their info via:
2017-06-05T10:44:46.894685+00:00 app[web.1]: npm ERR!     npm owner ls express-es6-rest-api
2017-06-05T10:44:46.895032+00:00 app[web.1]: npm ERR! There is likely additional logging output above.
2017-06-05T10:44:46.900200+00:00 app[web.1]: 
2017-06-05T10:44:46.900471+00:00 app[web.1]: npm ERR! Please include the following file with any support request:
2017-06-05T10:44:46.900611+00:00 app[web.1]: npm ERR!     /app/npm-debug.log
2017-06-05T10:44:46.989962+00:00 heroku[web.1]: Process exited with status 1
2017-06-05T10:44:47.002321+00:00 heroku[web.1]: State changed from starting to crashed
2017-06-05T10:46:42.536395+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/" host=xxx-backend.herokuapp.com request_id=178ed6ba-5aad-47d2-a08b-97d1af04275c fwd="81.205.254.193" dyno= connect= service= status=503 bytes= protocol=https
2017-06-05T10:46:43.240301+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/favicon.ico" host=xxx-backend.herokuapp.com request_id=e1578893-aa02-4544-832e-32a6a836e208 fwd="81.205.254.193" dyno= connect= service= status=503 bytes= protocol=https

Also Heroku CLI output is like this:

Writing objects: 100% (6/6), 761 bytes | 0 bytes/s, done.
Total 6 (delta 4), reused 0 (delta 0)
remote: Compressing source files... done.
remote: Building source:
remote: 
remote: -----> Node.js app detected
remote: 
remote: -----> Creating runtime environment
remote:        
remote:        NPM_CONFIG_LOGLEVEL=error
remote:        NPM_CONFIG_PRODUCTION=true
remote:        NODE_VERBOSE=false
remote:        NODE_ENV=production
remote:        NODE_MODULES_CACHE=true
remote: 
remote: -----> Installing binaries
remote:        engines.node (package.json):  unspecified
remote:        engines.npm (package.json):   unspecified (use default)
remote:        
remote:        Resolving node version 6.x via semver.io...
remote:        Downloading and installing node 6.10.3...
remote:        Using default npm version: 3.10.10
remote: 
remote: -----> Restoring cache
remote:        Loading 2 from cacheDirectories (default):
remote:        - node_modules
remote:        - bower_components (not cached - skipping)
remote: 
remote: -----> Building dependencies
remote:        Installing node modules (package.json)
remote: 
remote: -----> Caching build
remote:        Clearing previous node cache
remote:        Saving 2 cacheDirectories (default):
remote:        - node_modules
remote:        - bower_components (nothing to cache)
remote: 
remote: -----> Build succeeded!
remote: -----> Discovering process types
remote:        Procfile declares types -> web
remote: 
remote: -----> Compressing...
remote:        Done: 18.4M
remote: -----> Launching...
remote:        Released v10
remote:        https://xxx-backend.herokuapp.com/ deployed to Heroku
remote: 
remote: Verifying deploy... done.
To https://git.heroku.com/xxx-backend.git

I've tried changing:

• in package.json write npm start more explicit - "start": "node dist/index.js",

• Also Googling for Process exited with code: 127 (npm install) does not give relevant

via shershen