Nginx reverse-proxy for RethinkDB Admin UI

Nginx -> RethinkDB Admin

Start your rethinkdb instance with this flag:
`--bind all` (or `bind=all` in the configuration file for your instance)

Block external access to the web UI with these two commands:
`sudo iptables -A INPUT -i eth0 -p tcp --dport 8080 -j DROP`
`sudo iptables -I INPUT -i eth0 -s 127.0.0.1 -p tcp --dport 8080 -j ACCEPT`

Install nginx (if you haven't already):
`sudo apt-get install nginx`

Create a new virtual host (server block):
`sudo cp /etc/nginx/sites-available/default /etc/nginx/sites-available/rethinkdb`

Edit this file:
`sudo nano /etc/nginx/sites-available/rethink`

to say:
```
server {
  listen 80;
  server_name domain.com;
  
  location /rethinkdb-admin/ {
    auth_basic "Restricted";
    auth_basic_user_file /etc/nginx/.rethinkdb.pass;
    proxy_pass http://127.0.0.1:8080/;
    proxy_redirect off;
    proxy_set_header Authorization "";
  }
}
```
where `domain.com` is the host name (or IP address) of the server running the RethinkDB Admin UI.

Create username and password (make sure you have apache2-utils installed `sudo apt-get install apache2-utils`):
`cd /etc/nginx/`
`htpasswd -c .rethinkdb.pass <username>` where `<username>` is the username you want.
The command will ask you to enter the password for the username you chose.

start/restart nginx
`sudo service nginx start`
or
`sudo service nginx restart`

Verify it works:
Navigate to `http://domain.com/rethinkdb_admin` where domain.com is the host name (or IP address) of the server running the RethinkDB Admin UI.