Documenation update : nginx+gunicorn setup.

INSTALL

@@ -392,6 +392,68 @@ configuration in order to launch Apache.
 Nginx
 -----
 
+`Nginx <http://nginx.org/>`_ is a really fast HTTP server. Associated
+with `Green Unicorn <http://gunicorn.org/>`_, it gives you one of the
+best setup to serve python/Django applications. Modoboa's
+performances are really good with this configuration.
+
+To use this setup, first download and install those softwares
+(`Install gunicorn <http://gunicorn.org/install.html>`_ and `install
+nginx <http://wiki.nginx.org/Install>`_).
+
+Then, use the following sample *gunicorn* configuration (create a new
+file named *gunicorn.conf.py* inside Modoboa's root dir)::
+
+  backlog = 2048
+  bind = "unix:/var/run/gunicorn/modoboa.sock"
+  pidfile = "/var/run/gunicorn/modoboa.pid"
+  daemon = True
+  debug = False
+  workers = 2
+  logfile = "/var/log/gunicorn/modoboa.log"
+  loglevel = "info"
+
+To start gunicorn, execute the following commands::
+
+  $ cd <modoboa dir>
+  $ gunicorn_django -c gunicorn.conf.py
+
+Now the *nginx* part. Just create a new virtual host and use the
+following configuration::
+
+  upstream modoboa {
+	server      unix:/var/run/gunicorn/modoboa.sock fail_timeout=0;
+  }
+
+  server {
+        listen 443;
+        server_name <host fqdn>;
+        root <modoboa's root dir>;
+
+        access_log  /var/log/nginx/<host fqdn>.access.log;
+        error_log /var/log/nginx/<host fqdn>.error.log;
+
+        location /static/ {
+                autoindex on;
+        }
+
+        location / {
+                proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+                proxy_set_header Host $http_host;
+                proxy_redirect off;
+                proxy_set_header X-Forwarded-Protocol https;
+
+                if (!-f $request_filename) {
+			proxy_pass http://modoboa;
+                        break;
+                }
+        }
+  }
+
+Paste this content to your configuration (replace values between
+``<>`` with yours), restart *nginx* and enjoy a really fast
+application!
+
 Using default plugins
 =====================