I came to know that during pre-compilation of assets in production mode, Rails will take assets from 'app/assets' only by default if we do not require files explictly from any other specific sources like 'vendor/assets' and 'lib/assets'.
I've a question:
Will require_tree . load assets from 'vendor/assets' and 'lib/assets' ?
No, require_tree . will only load the assets in the local directory, hence the dot after require_tree, which specifies only the directory where the application asset file exists. If you want to include files in vendor/assets and lib/assets, you should do something like this (or similar for stylesheets):
//= require_tree ../../../vendor/assets/javascripts/.
//= require_tree ../../../lib/assets/javascripts/.
(From this question.)
