Adding the outline of a forge module

forge.nix

 { ... }:
 
 {
-  options = {};
+  options = {
+    enable = mkEnableOption "forge";
+
+    package = mkOption {
+      type = types.path;
+      default = pkgs.forge;
+      description = "Path to the forge sources";
+    };
+
+    bind = mkOption {
+      type = types.str;
+      default = "0.0.0.0";
+      description = "Address to bind forge server to";
+    };
+
+    port = mkOption {
+      type = types.integer;
+      default = 12220;
+      description = "The port to bind the (internal) forge server to";
+    };
+
+    route = mkOption {
+      type = types.str;
+      default = "/rebuild";
+      description = "The HTTP route to listen to";
+    };
+
+    tokenHash = mkOption {
+      type = types.str;
+      default = null;
+      description = ''
+        Your CI will use a token to send to the forge server as a secret.
+        This secret is used as a key to secure other secrets.
+
+        In order to verify the validity of an incoming request, forge
+        uses a salted SHA256 hash of the secret. You can use `forge-cli`
+        to generate this hash.
+      '';
+  };
+
   config = {};
 }