Google Material Icons font assets and form helpers
add material_icons-rails to your Gemfile
gem 'material_icons-rails'
Add to material-icons to your application.css
*= require material-icons
use a form helper in a view
material_icon(:face)
material_icon(:face, class: 'one-in-your-own-css and-another')
material_icon(:face, class: 'red', tag: 'span')
valid options
:size a string for font-size, an integer for px, 1x - 4x for pre-defined sizes