Add node modules and compiled JavaScript from main (#54)

Co-authored-by: Oliver King <oking3@uncc.edu>

node_modules/underscore/modules/extend.js

@@ -0,0 +1,5 @@
+import createAssigner from './_createAssigner.js';
+import allKeys from './allKeys.js';
+
+// Extend a given object with all the properties in passed-in object(s).
+export default createAssigner(allKeys);