finish the first version of patch_file

test/dummy/app/assets/javascripts/application.js

@@ -0,0 +1,13 @@
+// This is a manifest file that'll be compiled into application.js, which will include all the files
+// listed below.
+//
+// Any JavaScript/Coffee file within this directory, lib/assets/javascripts, vendor/assets/javascripts,
+// or vendor/assets/javascripts of plugins, if any, can be referenced here using a relative path.
+//
+// It's not advisable to add code directly here, but if you do, it'll appear at the bottom of the
+// compiled file.
+//
+// Read Sprockets README (https://github.com/sstephenson/sprockets#sprockets-directives) for details
+// about supported directives.
+//
+//= require_tree .