Add example for DH management

pillar.example

@@ -153,6 +153,14 @@ nginx:
           (Your Private Key: www.example.com.key)
           -----END RSA PRIVATE KEY-----
 
+    dh_contents: |
+      -----BEGIN DH PARAMETERS-----
+      (Your custom DH prime)
+      -----END DH PARAMETERS-----
+    # or to generate one on-the-fly
+    dh_keygen: true
+    dh_keysize: 2048
+
     # Passenger configuration
     # Default passenger configuration is provided, and will be deployed in
     # /etc/nginx/conf.d/passenger.conf
@@ -160,4 +168,3 @@ nginx:
       passenger_root: /usr/lib/ruby/vendor_ruby/phusion_passenger/locations.ini
       passenger_ruby: /usr/bin/ruby
       passenger_instance_registry_dir: /var/run/passenger-instreg
-