Problem Twitter Bootstrap Glyphicons not show in Heroku

The rails pipeline with Heroku is something difficult to master…

Today I had a problem that has taken some hours to be fixed.

I precompile assets as usual, and I realised that Glyphicon files have a different extension than the usual .js and .css, so I first had to extend it:

config.assets.precompile += %w( *.js *.css *.eot *.woff *.ttf *.svg )

Then I saw that the files were being produced correctly,

"twitter/bootstrap/glyphicons-halflings-regular-a6d95d67a6db3f50ff64b2103e8c9348.woff":{"logical_path":"twitter/bootstrap/glyphicons-halflings-regular.woff"

(excerpt of the manifest.json file)

But they did not show in Heroku

GET http://nexmot.getspeak.com/assets/twitter/bootstrap/glyphicons-halflings-regular.woff 404 (Not Found)

Although I could see them:

$ heroku run bash
$ ls public/assets

After some crazy investigation, this video gave me the solution:

You have to put this line in production.rb

config.assets.compile = true

To learn more, check out this excellent resources:
https://devcenter.heroku.com/articles/rails-4-asset-pipeline
http://guides.rubyonrails.org/asset_pipeline.html