Using Python Flask, AngularJS, test/production directories and serving requests

This is my first time doing a Python and AngularJS app so please bare with me. Any feedback is appreciated :D

Here is the setup:

Using ngBoilerplate (grunt, bower, angular, the works...) to create a SAP application. On my localhost, it launches a NodeJS server so I can test the app. This all works fine minus the database/apis. Using Grunt, it will create a /build folder (which is all the non-minified source,assets, for debugging) and a /bin folder with the production code.

For the backend I have a Python flask app (which I'll use for REST API's) on Heroku. Inside the main Python script:

@app.route("/")
def index():
    #index.html has the angular SAP
    return make_response( open('build/index.html').read() )

I push the code to Heroku, it detects a Python app (which I believe is good as I will need Python to make my api requests), and it serves the correct index.html. I see Angular making requests to /vendor/angular.js /css/angular.css etc, when those files technically live in /build/vendor/angular.js.

I'm not sure if I'm suppose to tell Angular where to grab the files or if it's Python related.

Am I suppose to change the DOCROOT (WWW) like in LAMP land? Do I change the routeprovider/urlrouterprovider in Angular to tell it to serve the files to a different location? Or do I change what I'm doing in Python?

The project directory looks like:

hellworld.py
requirements.txt
runp-heroku.py
procfile
Gruntfile.js
build/       //test code
  assets/
  index.html
  vendor/
bin/         //production code
  assets/
  index.html
  vendor/
src/         //original code
  assets/
  index.html
  vendor/