November 2015 EDIT: I would recommend this gem: https://github.com/twbs/bootstrap-sass It is actively maintained by the Bootstrap community and works really well with Ruby on Rails.
I was having a very similar issue as you but I figure it out! Find this part in your bootstrap.css file:
@font-face {
font-family: 'Glyphicons Halflings';
src: url('../fonts/glyphicons-halflings-regular.eot');
src: url('../fonts/glyphicons-halflings-regular.eot?#iefix') format('embedded-opentype'), url('../fonts/glyphicons-halflings-regular.woff') format('woff'), url('../fonts/glyphicons-halflings-regular.ttf') format('truetype'), url('../fonts/glyphicons-halflings-regular.svg#glyphicons_halflingsregular') format('svg');
}
and replace ../fonts/
with /assets
. This is what your final code will look like.
@font-face {
font-family: 'Glyphicons Halflings';
src: url('/assets/glyphicons-halflings-regular.eot');
src: url('/assets/glyphicons-halflings-regular.eot?#iefix') format('embedded-opentype'), url('/assets/glyphicons-halflings-regular.woff') format('woff'), url('/assets/glyphicons-halflings-regular.ttf') format('truetype'), url('/assets/glyphicons-halflings-regular.svg#glyphicons_halflingsregular') format('svg');
}
I hope this helped!