new git-hooks based deployment

module.nix

@@ -0,0 +1,58 @@
+{ config, pkgs, lib, ... }:
+{
+  options.services.fooud = {
+    enable = lib.mkEnableOption config.description;
+    repos = lib.mkOption {
+      type = lib.listOf {
+        path = lib.mkOption {
+          description = "fullpath to the repositiory on your server";
+          type = lib.types.string;
+        };
+        hooks = lib.mkOption {
+          type = lib.listOf lib.types.path;
+          example = [
+            pkgs.writeScriptBin "post-recieve" ''
+              git clone . /var/www/your/deployed/location
+            ''
+          ];
+        };
+      };
+    };
+    user = lib.mkOption {
+      type = lib.types.str;
+      default = "fooud-deploy";
+    };
+  };
+
+  config = let
+    cfg = config.services.fooud;
+  in lib.mkIf cfg.enable {
+    users.users."${cfg.user}" = {
+      group = "${cfg.user}";
+      isSystemUser = true;
+      createHome = true;
+      home = "/var/lib/${cfg.user}";
+      shell = "${pkgs.git}/bin/git-shell";
+    };
+    users.groups."${cfg.user}" = {};
+
+    systemd = {
+      services."fooud" = {
+        wantedBy = [ "multi-user.target" ];
+        serviceConfig = {
+          Type = "oneshot";
+          User = cfg.user;
+          ExecStart = pkgs.writeScriptBin "fooud-deploy"
+            (lib.concatMapStrings
+              (repo: ''
+                if [ -d ${repo.path} ]; then
+                  rm -f ${repo.path}/hooks/*
+                  cp ${repo.hooks}/bin/* ${repo.name}/hooks/
+                fi
+              '')
+            cfg.repos);
+        };
+      };
+    };
+  };
+}