I am doing assets pre-compile, and running the application in production mode. After compilation when I load the my index page I got followings warnings in the chrome consol
Go to the address below on GitHub and download each of the FontAwesome files.
https://github.com/FortAwesome/font-awesome-sass/tree/master/assets/fonts/font-awesome
...but instead of right-clicking and saving the link as, click on each of the files and use the 'Download' button to save them.
I found that saving the link as downloaded an HTML page and not the FontAwesome file binary itself.
Once I had all of the binaries it worked for me.