Can't get Django/Postgres app settings working on Heroku
Have you set your DJANGO_SETTINGS_MODULE environment variable? I believe what is happening is this: by default Django is using your local.py settings, which is why it's trying to connect on localhost.
To make Django detect and use your production.py settings, you need to do the following:
heroku config:set DJANGO_SETTINGS_MODULE=settings.production
This will make Django load your production.py settings when you're on Heroku :)
I'm making a Django app with the Two Scoops of Django template. Getting this Heroku error, are my Postgres production settings off? 

OperationalError at /
could not connect to server: Connection refused
Is the server running on host "localhost" (127.0.0.1) and accepting
TCP/IP connections on port 5432?
Exception Location: /app/.heroku/python/lib/python2.7/site-packages/psycopg2/__init__.py
foreman start works fine
Procfile: web: python www_dev/manage.py runserver 0.0.0.0:$PORT --noreload 
local.py settings: 
DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.postgresql_psycopg2',
        'NAME': 'www',
        'USER': 'amyrlam',
        'PASSWORD': '*',
        'HOST': 'localhost',
        'PORT': '5432',
    }
}
production.py settings: commented out local settings from above, added standard Heroku Django stuff:  
import dj_database_url
DATABASES['default'] =  dj_database_url.config()
SECURE_PROXY_SSL_HEADER = ('HTTP_X_FORWARDED_PROTO', 'https')
ALLOWED_HOSTS = ['*']
import os
BASE_DIR = os.path.dirname(os.path.abspath(file))
STATIC_ROOT = 'staticfiles'
STATIC_URL = '/static/'
STATICFILES_DIRS = (
    os.path.join(BASE_DIR, 'static'),
)
UPDATE: production settings, tried changing:

import dj_database_url
DATABASES['default'] =  dj_database_url.config(default=os.environ["DATABASE_URL"])
(named my Heroku color URL to DATABASE_URL, same link in heroku config)