add csurf type file

csurf/csurf.d.ts

@@ -0,0 +1,30 @@
+// Type definitions for csurf
+// Project: http://expressjs.com
+// Definitions by: Hiroki Horiuchi <https://github.com/horiuchi/>
+// Definitions: https://github.com/borisyankov/DefinitelyTyped
+
+/// <reference path="../express/express.d.ts" />
+
+declare module Express {
+  export interface Request {
+    csrfToken(): string;
+  }
+}
+
+declare module "csurf" {
+  import express = require('express');
+
+  function csurf(options?: {
+    value?: (req: express.Request) => string;
+    cookie?: csurf.CookieOptions;
+  }): express.RequestHandler;
+
+  module csurf {
+    export interface CookieOptions extends express.CookieOptions {
+      key: string;
+    }
+  }
+
+  export = csurf;
+}
+