Added the underscore node_module.

node_modules/underscore/amd/tap.js

@@ -0,0 +1,13 @@
+define(function () {
+
+  // Invokes `interceptor` with the `obj` and then returns `obj`.
+  // The primary purpose of this method is to "tap into" a method chain, in
+  // order to perform operations on intermediate results within the chain.
+  function tap(obj, interceptor) {
+    interceptor(obj);
+    return obj;
+  }
+
+  return tap;
+
+});