Add fontawesome dependency

Gemfile

 # Use HAML for templates
 gem 'haml'
 
+# Use Fontawesome icons
+gem 'font-awesome-sass'
+
 # Use Capistrano for deployment
 # gem 'capistrano-rails', group: :development
 

Gemfile.lock

     erubis (2.7.0)
     execjs (2.7.0)
     ffi (1.9.14)
+    font-awesome-sass (4.7.0)
+      sass (>= 3.2)
     globalid (0.3.7)
       activesupport (>= 4.1.0)
     haml (4.0.7)
   bootstrap-sass (~> 3.3.6)
   byebug
   coffee-rails (~> 4.2)
+  font-awesome-sass
   haml
   jbuilder (~> 2.5)
   jquery-rails