Nginx server configuration with Unicorn for a spree site, running ssl and non-ssl side by side

nginx.conf

upstream unicorn {
  server unix:/tmp/unicorn.store.sock fail_timeout=0;
}

server {
  listen 80 default deferred;

# To enable ssl on your server for checkout and admin functionality
# add this line
  listen 443 ssl;

  # server_name example.com;
  root /home/deployer/apps/store/current/public;

# Add these according to the location of the ssl keys
  ssl_certificate       /home/deployer/.ssl_keys/server.crt;
  ssl_certificate_key   /home/deployer/.ssl_keys/server.key;

  location ^~ /assets/ {
    gzip_static on;
    expires max;
    add_header Cache-Control public;
  }

  try_files $uri/index.html $uri @unicorn;
  location @unicorn {
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header Host $http_host;

# Add this for proxy to work on ssl
    proxy_set_header X-Forwarded-Proto $scheme;
    proxy_redirect off;
    proxy_pass http://unicorn;
  }

  error_page 500 502 503 504 /500.html;
  client_max_body_size 4G;
  keepalive_timeout 10;
}