'502 Bad Gateway' when using gunicorn/nginx/django1.7

i installed django on ubuntu using the one-click install, and am now trying to import an existing django project.

using python manage.py runserver 0:9000 i have no problem, if i go to my site address, i see my project. but if i stop the django ‘runserver’ and run service gunicorn restart, then visit my page, i get a ‘502 Bad Gateway’ error.

i did upgrade my droplet’s django to 1.7 using pip install --upgrade. everything else seems to be working fine

on a related point… i am new to servers, and still unclear of what nginx, gunicorn, and wsgi are, and what the flow of information is between them, so if someone could briefly explain that, or point me to a good tutorial, much appreciated.

my nginx error log says the following:

2015/02/25 16:53:16 [error] 1052#0: *191 connect() failed (111: Connection refused) while connecting to upstream, client: 76.98.74.102, server: _, request: "GET /home/ HTTP/1.1", upstream: "http://127.0.0.1:9000/home/", host: "104.236.29.98"

my django project is in /home/django/myproject/

/etc/init/gunicorn.conf:

start on (local-filesystems and net-device-up IFACE=eth0)
stop on runlevel [!12345]

respawn 

setuid django
setgid django
chdir /home/django

exec gunicorn \
    --name=open_elections \
    --pythonpath=open_elections \
    --bind=0.0.0.0:9000 \
    --config /etc/gunicorn.d/gunicorn.py \
    open_elections.wsgi:application

/etc/nginx/sites-available/myproject:

upstream app_server {
    server 127.0.0.1:9000 fail_timeout=0;
}

server {
    listen 80 default_server;
    listen [::]:80 default_server ipv6only=on;

    root /usr/share/nginx/html;
    index index.html index.htm;

    server_name localhost;

    keepalive_timeout 5;

    location /media  {
        alias /home/django/myproject/media;
    }

    location /static {
        alias /home/django/myproject/mysite/static; 
    }

    location / {
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header Host $http_host;
        proxy_redirect off;
        proxy_pass http://app_server;
    }

}

mproject/mysite/wsgi.py:

import os
os.environ.setdefault("DJANGO_SETTINGS_MODULE", "mysite.settings")

from django.core.wsgi import get_wsgi_application
application = get_wsgi_application()