Merge pull request #2244 from vikhyat/css-import

Site Customization @import fixes

app/models/site_customization.rb

@@ -14,12 +14,26 @@ class SiteCustomization < ActiveRecord::Base
   end
 
   def compile_stylesheet(scss)
+    # Get the sprockets environment. In production Rails.application.assets is a
+    # Sprockets::Index instead of Sprockets::Environment, there is no cleaner way
+    # to get the environment from the index.
+    env = Rails.application.assets
+    if env.is_a?(Sprockets::Index)
+      env = env.instance_variable_get('@environment')
+    end
+
+    context = env.context_class.new(env, "custom.scss", "app/assets/stylesheets/custom.scss")
+
     ::Sass::Engine.new(scss, {
       syntax: :scss,
       cache: false,
       read_cache: false,
       style: :compressed,
-      filesystem_importer: DiscourseSassImporter
+      filesystem_importer: DiscourseSassImporter,
+      sprockets: {
+        context: context,
+        environment: context.environment
+      }
     }).render
 
   rescue => e