feat(auth): implement user authentication system

backend/node_modules/@sinonjs/commons/lib/global.js

@@ -0,0 +1,21 @@
+"use strict";
+
+/**
+ * A reference to the global object
+ * @type {object} globalObject
+ */
+var globalObject;
+
+/* istanbul ignore else */
+if (typeof global !== "undefined") {
+    // Node
+    globalObject = global;
+} else if (typeof window !== "undefined") {
+    // Browser
+    globalObject = window;
+} else {
+    // WebWorker
+    globalObject = self;
+}
+
+module.exports = globalObject;