Added the underscore node_module.

node_modules/underscore/modules/tap.js

@@ -0,0 +1,7 @@
+// 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.
+export default function tap(obj, interceptor) {
+  interceptor(obj);
+  return obj;
+}