Make Caddy the default web server

module.nix

@@ -13,20 +13,46 @@ in
     hostName = mkOption {
       type = types.str;
       description = ''
-        Name for the nginx virtual host.
+        Name for the virtual host for the web server.
       '';
       example = "example.org";
     };
+
+    server = mkOption {
+      type = types.enum [ "nginx" "caddy" ];
+      description = ''
+        The web server to be used for serving Financier. Either "nginx"
+        or "caddy".
+      '';
+      default = "caddy";
+      example = "example.org";
+    };
   };
 
   config = mkIf cfg.enable {
     networking.firewall.allowedTCPPorts = [ 80 443 ];
 
-    services.nginx.virtualHosts."${cfg.hostName}" = {
+    services.nginx = mkIf (cfg.server == "nginx") {
+      enable = true;
+
+      virtualHosts."${cfg.hostName}" = {
         forceSSL = true;
         enableACME = true;
         root = financier-dist;
         locations."/".tryFiles = "$uri $uri/ /index.html";
       };
     };
+
+    services.caddy = mkIf (cfg.server == "caddy") {
+      enable = true;
+
+      config = ''
+        ${cfg.hostName} {
+          root * ${financier-dist}
+          file_server
+          try_files {path} {path}/ /index.html
+        }
+      '';
+    };
+  };
 }