Added firmware package

MMDVMHost/module.nix

@@ -0,0 +1,50 @@
+{ lib, config, pkgs, mmdvm_host, ... }:
+with lib;
+let
+  # Shorter name to access final settings a 
+  # user of hello.nix module HAS ACTUALLY SET.
+  # cfg is a typical convention.
+  cfg = config.services.mmdvm_host;
+in
+{
+
+  options.services.mmdvm_host = {
+    enable = mkEnableOption "MMDVMHost service";
+    package = mkOption {
+      default = mmdvm_host.x86_64-linux.default;
+      type = types.package;
+    };
+    user = mkOption {
+      type = types.str;
+      default = "afg";
+    };
+  };
+
+
+  config = mkIf cfg.enable {
+    # List packages installed in system profile. To search, run:
+    # $ nix search wget
+    environment.systemPackages = [
+      cfg.package
+    ];
+
+    systemd.services.mmdvm_host = {
+      wantedBy = [ "multi-user.target" ];
+      wants = [ "network.target" ];
+      after = [ "network.target" ];
+      description = "MMDVMHost service";
+      serviceConfig = {
+        Type = "exec";
+        User = cfg.user;
+        Restart = "always";
+        RestartSec = "3s";
+        StartLimitIntervalSec = "0";
+        RuntimeDirectory = "MMDVMHost";
+      };
+      script = ''
+        exec ${cfg.package}/bin/MMDVMHost
+      '';
+    };
+  };
+
+}