This is my application.js manifest.
//= require jquery
//= require jquery_ujs
//= require jquery.purr
//= require best_in_place
//= require jquery-ui
//= require bootstrap-dropdown
//= require bootstrap-modal
//= require_tree .
With this setup, sortable (JQuery), dropdowns (bootstrap) and modals (bootstrap) work in PRODUCTION on heroku.
In DEVELOPMENT, the dropdowns do NOT work.
When I place the bootstrap requires ABOVE jquery, ALL bootstrap and jquery stop working.
I fixed the local drop down not working by using config.serve_static_assets = false in development.rb.
I am leaving the question in place to reference as an acceptable order for the 'requires' within the application.js manifest.