docs/roundcube: add caddy example

docs/roundcube-caddy.nix

@@ -0,0 +1,17 @@
+{ config, ... }:
+{
+  services.nginx.virtualHosts.${config.services.roundcube.hostName} = {
+    forceSSL = false;
+    enableACME = false;
+    listen = [
+      {
+        addr = "127.0.0.1";
+        port = 8000;
+      }
+    ];
+  };
+
+  services.caddy.virtualHosts."${config.services.roundcube.hostName}".extraConfig = ''
+    reverse_proxy localhost:8000
+  '';
+}

docs/roundcube.rst

@@ -17,3 +17,10 @@ Once set up you can login with your login account credentials.
 
 .. literalinclude:: ./roundcube.nix
    :language: nix
+
+To use a different reverse proxy, such as Caddy, bind Roundcube's Nginx virtual
+host to ``127.0.0.1`` on a custom port and disable SSL and ACME, as the reverse
+proxy will handle those.
+
+.. literalinclude:: ./roundcube-caddy.nix
+   :language: nix