You are technically approaching the problem from the wrong direction. Your config.assets.precompile should reference only a few central manifest type files (for example, application.js), and the manifest files then reference the js files as necessary.
For example, your application.js might look like:
//= require highcharts.js
//= require schedule.js
//= require new_event.js
//= require old_event.js
//= require event_controls.js
//= require other_stuff.js
Set up like this, all the listed files will be included in the precompiled version of application.js, and application.js is the only file you will need to include in your layout.
To have new files added automatically, you can use instead
//= require_tree .
which will include every .js file in the same directory as application.js, plus those in all the child directories.
In practice, one application.js file that includes every single js file in the application is a bit much. You can break your files down into a collection of central manifests. For example, charts.js, events.js, misc.js. Add these files to your config.assets.precompile. Then when a new file is required, update the manifest files and not the production.rb file.
