Bundle brainstorm server dependencies instead of requiring npm install

Vendor node_modules into the repo so the brainstorm server works
immediately on fresh plugin installs without needing npm at runtime.

skills/brainstorming/scripts/node_modules/cookie-signature/index.js

@@ -0,0 +1,51 @@
+/**
+ * Module dependencies.
+ */
+
+var crypto = require('crypto');
+
+/**
+ * Sign the given `val` with `secret`.
+ *
+ * @param {String} val
+ * @param {String|NodeJS.ArrayBufferView|crypto.KeyObject} secret
+ * @return {String}
+ * @api private
+ */
+
+exports.sign = function(val, secret){
+  if ('string' !== typeof val) throw new TypeError("Cookie value must be provided as a string.");
+  if (null == secret) throw new TypeError("Secret key must be provided.");
+  return val + '.' + crypto
+    .createHmac('sha256', secret)
+    .update(val)
+    .digest('base64')
+    .replace(/\=+$/, '');
+};
+
+/**
+ * Unsign and decode the given `val` with `secret`,
+ * returning `false` if the signature is invalid.
+ *
+ * @param {String} val
+ * @param {String|NodeJS.ArrayBufferView|crypto.KeyObject} secret
+ * @return {String|Boolean}
+ * @api private
+ */
+
+exports.unsign = function(val, secret){
+  if ('string' !== typeof val) throw new TypeError("Signed cookie string must be provided.");
+  if (null == secret) throw new TypeError("Secret key must be provided.");
+  var str = val.slice(0, val.lastIndexOf('.'))
+    , mac = exports.sign(str, secret);
+  
+  return sha1(mac) == sha1(val) ? str : false;
+};
+
+/**
+ * Private
+ */
+
+function sha1(str){
+  return crypto.createHash('sha1').update(str).digest('hex');
+}