Relax font-awesome-rails dependency to ~> 4.7

Signed-off-by: Rémy Coutable <remy@rymai.me>

Gemfile

@@ -231,7 +231,7 @@ gem 'uglifier', '~> 2.7.2'
 
 gem 'addressable',        '~> 2.3.8'
 gem 'bootstrap-sass',     '~> 3.3.0'
-gem 'font-awesome-rails', '~> 4.6.1'
+gem 'font-awesome-rails', '~> 4.7'
 gem 'gemojione',          '~> 3.0'
 gem 'gon',                '~> 6.1.0'
 gem 'jquery-atwho-rails', '~> 1.3.2'

Gemfile.lock

@@ -878,7 +878,7 @@ DEPENDENCIES
   fog-local (~> 0.3)
   fog-openstack (~> 0.1)
   fog-rackspace (~> 0.1.1)
-  font-awesome-rails (~> 4.6.1)
+  font-awesome-rails (~> 4.7)
   foreman (~> 0.78.0)
   fuubar (~> 2.0.0)
   gemnasium-gitlab-service (~> 0.2)