I'm new to grunt.  I'm coming from rails and getting into angular.  From what I can see grunt usemin can replace <script src=...> between build directives and replace that with a single minified js during grunt build.  That's great for deployment.  
However whenever I add new angular controllers during development, I also have to remember to add them to my index.html. That's a hassle, and the same goes for if I move my feature folders around, I have to change all my src paths in index.html.
It would be nice if in development, grunt would watch all my src/**/*.js and automatically add them all to index.html for me... similar to rails asset pipeline and asset manifest that just does require_tree when you're developing.  You can put files anywhere and it's automatically available.  
Is there such an existing solution or example for a grunt watcher? Thanks